Ecclesiastes 3 is, in popular culture, sort of a cliche. The words are familiar to most people, even if they can't place where they originally came from. It is a song, it is a poem, it is a saying on a facebook post. It means different things to different people, but most of the time, it is a superficial glance at words which can be twisted to mean whatever you want them to mean.
But when you really dig into the passage, there is a lot of substance. It isn't a whimsical statement at all. It is clear direction on how we, as Christians, should live.