If you count on reasons for smile, then you will note that there is no obvious reason to smile.
Our life is so hectic that we almost lost our smile in a huge piles of work. Some people are busy in coding, some are busy in marketing, some are teaching, some are clicking the moods of others and forgetting about themselves.
This is how we are living today.
We all have learned the art of juggling. Somewhere somehow we all have lost the essence of life.
" The secret to living well and longer is :
eat half,
walk double,
laugh triple,
and laugh without measure."
So smile, to make life more beautiful and even if you are in problem, your smile will make you strong. So don't let your lips to know the problem.