We've all experienced that feeling that comes when your phone makes a sound to tell you that its battery level is low. It often comes at the worst times – when you're out on a trip and don't have a charger, or when you're expecting an important phone call.

    Indeed, this feeling is so common that South Korean electronics manufacturer LG has given it a name: low battery anxiety.

    According to a survey of 2,000 US adults conducted by the company last year, 90 percent of respondents said that they panic if their battery level reaches 20 percent or lower.

    And last month, UK telecommunications service provider 02 found that around 15.5 million Britons live in “constant fear” of their mobile phones running out of power, according to a survey by the company.

    “The problem is not about being unable to make calls, but is rooted in the fact that smartphones are now where we store digital memories,” noted the Daily Mail.

    However, battery worries don't just affect smartphone lovers. Many owners of electric vehicles also suffer from so-called “range anxiety”. This refers to the concern that the vehicle may not make it to its destination before the power runs out.

    Meanwhile, it isn't just low power that people worry about. A study carried out by South Korea's Sungkyunkwan University and China's City University of Hong Kong found that many of us also worry about not having constant access to our phone.

    This condition is known as nomophobia, short for “no mobile phone phobia（恐惧症）”. Symptoms include feeling uncomfortable when access to one's phone isn't possible, being unable to turn off your phone, and constantly topping up the battery to make sure it never dies.

    So, why do so many people treat their smartphone with such importance? The underlying reason may be that they keep us connected to the people around us, and if we're unable to use our phone, we feel like we're cut off from our social life.

    With products with bigger batteries being released all the time though - such as Xiaomi's Mi Max smartphone range or Tesla's Model S cars – battery anxiety may hopefully soon be a thing of the past.

    At your next meeting, wait for a pause in conversation and try to measure how long it lasts.

    Among English speakers, chances are that it will be a second or two at most. But while this pattern may be universal, our awareness of silence differs dramatically across cultures.

    What one culture considers a confusing or awkward pause may be seen by others as a valuable moment of reflection and sign of respect for what the last speaker has said. Research in Dutch and also in English found that when a silence in conversation stretches to four seconds, people start to feel uneasy. In contrast, a separate study of business meetings found that Japanese people are happy with silences of 8.2 seconds — nearly twice as long as in Americans' meetings.

    In Japan, it is recognized that the best communication is when you don't speak at all. It's already a failure to understand each other by speaking because you're repairing that failure by using words.

    In the US, it may originate from the history of colonial (殖民地) America as a crossroads of many different races. When you have a complex of difference, it's hard to establish common understanding unless you talk and there's understandably a kind of anxiety unless people are verbally engaged to establish a common life. This applies also to some extent to London.

    In contrast, when there's more homogeneity, perhaps it's easier for some kinds of silence to appear. For example, among your closest friends and family it's easier to sit in silence than with people you're less well acquainted with.

    It is good to get in touch with your inner child from time to time, and obviously some people are willing to pay big money for the chance to do so in a proper environment. A Brooklyn-based adult preschool is charging customers between $333 and $999 for the chance to act like a kid again.

    At Preschool Mastermind in New York adults get to participate in show—and—tell, arts—and—crafts such as finger paint, games like musical chairs and even take naps. The month-long course also has class picture day where the adults are expected to have a field trip and a parent day.

    30-year-old Michelle Joni Lapidos, the brain behind the adult preschool, studied childhood education and has always wanted to be a preschool teacher. She's always on the lookout for new ways to get people in touch with the freedom of childhood. A friend encouraged her to start the mastermind course instead.

    According to Candice, her blogger friend, Preschool Mastermind gives adults a chance to relearn and master the things that they failed to understand as children. "I realized all the significances of what we learn in preschool," said founder Michelle Joni, "People come here and get in touch with their inner child. It's magical. We are bringing ourselves back to another place, another time with ourselves when we are more believing in ourselves, more confident and ready to take on the world."

    "One person's here because they want to learn not to be so serious." Michelle said. "Another's here to learn to be more confident." She explained that most of the classes were planned. However, Joni added that while the planned activities were fun, it was often the spontaneous(自发的)moments that attracted students. "It's the things you don't plan for, the sharing between friends and learning from each other."

    In many countries, authority is seldom questioned, either because it is highly respected, or because it is feared. Because rank has been important in certain societies for a long time, people have been trained never to question those in authority. For example, children are not expected to question their teachers in school. It may be considered improper for young businessmen to suggest ideas that differ from those of older, more experienced members of the business.

    In other countries, including America, children are trained to question and search for answers. When a child asks a question, he will often be told to go to the library and find the answer for himself. By the time students reach the age of 14 or 15, they may be developing exciting new ideas in all fields of science and arts. To encourage such creativity, there are many national prizes offered to students every year for their scientific discoveries and artistic accomplishments.

    This interest in questioning and searching may be considered by some people as bad for young people's manners, that young people lack respect for authority. This impression may be created when visitors notice young Americans asking questions and arguing with older people. However, this is because many Americans have a different attitude toward authority than may exist in other areas of the world. In a work or business situation, ideas are freely and openly discussed and argued. It is important to remember that it is the person's ideas that are being questioned, not the individual himself. The two are quite separate. The purpose of the searching, questioning, and arguing is to find the facts in a particular situation, and therefore a solution, so that the work of the business can progress in the most effective manner possible.

    As was mentioned earlier, you may notice the same questioning in social conversations. Although some individual may think that Americans are rude because of the direct manner with people, they are merely trying to learn more about your ideas.

    Here is an astonishing and significant fact: Mental work alone can't make us tired. It sounds absurd. But a few years ago, scientists tried to find out how long the human brain could labor without reaching a stage of fatigue(疲劳). To the amazement of these scientists, they discovered that blood passing through the brain, when it is active, shows no fatigue at all! If we took a drop of blood from a day laborer, we would find it full of fatigue toxins(毒素)and fatigue products. But if we took blood from the brain of an Albert Einstein, it would show no fatigue toxins at the end of the day.

    So far as the brain is concerned, it can work as well and swiftly at the end of eight or even twelve hours of effort as at the beginning. The brain is totally tireless. So what makes us tired?

    Some scientists declare that most of our fatigue comes from our mental and emotional(情感的)attitudes. One of England's most outstanding scientists, J. A. Hadfield, says, "The greater part of the fatigue from which we suffer is of mental origin. In fact, fatigue of purely physical origin is rare. "Dr. Brill, a famous American scientist, goes even further. He declares, "One hundred percent of the fatigue of a sitting worker in good health is due to emotional problems. "

    What kinds of emotions make sitting workers tired? Joy? Satisfaction? No! A feeling of being bored, anger, anxiety, tenseness, worry, a feeling of not being appreciated—those are the emotions that tire sitting workers. Hard work by itself seldom causes fatigue. We get tired because our emotions produce nervousness in the body.

    July 16th was a bad day for Mr. Arthur Johnson. In the morning, he set out from his home in Santa Barbara, California. It was the start of his summer holidays and he decided to visit Wends at Las Vegas, then he hoped to go fishing in Lake Mead, 40 km from Las Vegas.

    Johnson's troubles started while he was driving happily across the Mojave Desert. His car went wrong and he tried to repair it. Then, to make matters worse, his attempts to start the car used up the battery (电池) and left it useless. After Johnson had waited an hour in the hot sun, a Canadian driver, John Williams, stopped and tried to help him. When both men failed, Williams promised to telephone a workshop to ask it to send a truck to pull the car away and repair its fuel pump.

    Johnson left the keys in his car and sat in the shade of a large tree. Soon he fell asleep. While he was sleeping, a repair truck arrived from San Pedro (the nearest town) and pulled his car away. Later on, Johnson woke up and thought that somebody had stolen his car. He started to walk back towards San Pedro but a police car stopped him to find out why he was walking in the desert.

    Johnson looked like a man wanted in Los Angels for robbery, so the police detained him at San Pedro for the night. The next day, Johnson telephoned his friends in Los Angeles. They drove to San Pedro and made the police believe that Johnson was a harmless salesman, so they set him free.