Our brain doesn't know how to be happy, or even content. It simply lacks the genetic instructions to carry out that task. It knows how to do a million other less important things, from writing a letter to maintaining our balance; from appreciating the music of Bach to smelling a rose, but if you ask the brain to be happy, it simply doesn't know how to respond.

This is because the genetic code is only concerned with survival and reproduction, which happiness does not necessarily have anything to do with, and therefore belongs in a different aspect. Nature doesn't want us to always feel content and satisfied, let alone happy, as this would lower our guard against possible threats to our survival.

Happiness, as the Brazilian poet Vinicius de Moraes put it, is “like a feather flying in the air. It flies light, but not for very long.” It is so elusive that it has also been compared to a butterfly, which “when pursued, is always just beyond your grasp, but which, if you will sit down quietly, may alight upon you,” according to 19th-century American novelist Nathaniel Hawthorne. In any case, what is clear is that happiness is, at best, fleeting (飞逝的） and inconstant.

In this blog, we will look at the myth of happiness from many perspectives and, in the process, we will touch on topics such as happy personalities, the unhappy workings of the brain, evolution, dreams, and even fairy tales. I explore all these issues in detail in my book, which shares its title with this blog. Happiness is a crucial concept. We spend all of our lives pursuing it, so it deserves a very careful analysis.

We are determined by our biological design to experience mixed and messy emotions. But the silver lining is the knowledge that having difficult emotions doesn't represent a personal failure. The inevitable unhappiness that we all suffer from time to time is not a shortcoming that demands urgent repair. Far from it. This unhappiness is, in fact, what makes us human.

A letter written to a 12-year-old girl in Lithuania was delivered in December, almost 51 years after it was sent by a pen pal in Poland. “I thought that someone was pranking me,” said Genovefa Klonovska after being handed the letter, which included a handmade colored rose and two paper dolls.

The letter, together with 17 others, fell out of a ventilation hole (通风口) this summer, dirty and wrinkled, as a wall was taken down in a former post office on the suburb of Vilnius. Jurgis Vilnius, owner of the building immediately called the post office. “I’m so happy they got interested,” said he.

Street names and their numbering have changed in Vilnius, and post office workers spent months looking for the right houses and talking to current renters and neighbors, tracking down where the recipients moved to. Only five were found. In several cases children of late recipients were handed a lost letter.

“We felt a moral duty to do this,” said Deimante Zebrauskaite, head of the customer experience department at Lithuania Post.

One lady compared the experience to receiving a message from a bottle thrown into sea. People were emotional. “Some felt they saw a part of daily life of their deceased parents,” Zebrauskaite said.

In the letter to Klonovska, sent from Koezary in Poland and stamped in 1970, a girl named Ewa complains buses no longer reach her village, so she has to walk in minus 23 degree Celsius cold, and asks for pictures of actors.

Now in her 60s, Klonovska has no memory of Ewa. She probably wrote Ewa after finding her address advertising for pen pals in a newspaper, and the relationship ceased after the letter got undelivered.

“So good that the letter didn't matter much. The loss was not life-changing,” said Klonovska “What if they delivered a lost letter from a suitor (求婚者) to his love, and their wedding never happened?”

As you grow rapidly through your teenage years, you will experience a lot of changes. The changes may seem difficult and they may seem to happen quickly. Don’t panic! You will deal successfully with them! You are a young adult now!

With more responsibility, you will find more freedom to make your own choices. This is a time to be well informed about your choices so that you can make healthy balanced decisions that will help shape your future. You may already know your career path or you may have no idea at all what you want to do. Both situations are fine! Work hard and the right opportunity will present itself to you.

Young adulthood means greater freedom and more choices. You will probably want to be independent. But try not to shut your family out of your life. You should learn to think of others even though you are old enough to look after yourself. Your family have been with you since you came into this world.

It is also perfectly natural in this time for you to spend more time with your friends than your family. Choose your friends wisely. A true friend will stand by you no matter what happens.

This period is part of the life cycle. There are some people who will be with you throughout life’s journey and there will be some people with whom you part and go separate ways. Leaving school can be hard. The reality is that you may not ever see all of your classmates again.

You are a young adult. It is your life. No one can live it for you. The choices that you make from now on will be your choices. So making the right choices will be important to you. Life is for living. Enjoy your life wisely!