It's the thing that every human seek for, I believe.

In fact, I feel that the people nowadays, should live happier than last time.

With technology, you get to contact your friends easier.
By understanding more about human rights, people know what they can actually ask for
By understanding the freedom they have - people get to choose the subject they want to study, the job they want to work (and leave the job if they're really unhappy about it)

People can sing in the pub if they want to.
People can take the photograph if they want to.
People can choose the country they want to live in.

But but but.... by abusing the rights.... one might potentially make the people around unhappy - while you are selfishly happy on your own.

Is that the reason why we see some people nowadays, who seemingly look happy, but is unhappy inside?

It's all about the balance, after all.