Don't trust every happy smile you see

I was talking to my friend a long time ago and we were talking about happiness...
then I don't know why but we...or rather she...said that the people who look the happiest are the ones who are most depressed...
in other words...if you see someone who looks happy...maybe he or she is not happy at all...
the happiness that is being shown is just a disguise...a mask that they wear...
they may have some problems that they cannot say to other people...
so they buried the problems in their hearts and they accumulates through time...
people hate if other people see them as vulnerable or weak...
that's why many depressed people put up a show so that other people won't know that they are actually sad...
by being happy they also are trying not to fall deeper into their depression...
it's like their way of convincing themselves that it's alright, that they can go on with their lives...
it's not that I want to say that happy people are sad and depressed people...no..no...
all I want to say is the next time you say someone who is happy...think again...maybe under that 'happy' smile, he or she has some problems...
so don't trust every smile you see...