Some people say that kind of music we hear, impacts us. Choice of music closely depends on the mood we are in. Just like mood selects the music, sometimes music generates the mood.
Last few months have seen a series of popular songs. These songs were played everywhere, from auto & buses to hair-dresser & dhabas to restaurants and so on. This created an environment or better word to use here is 'mood' that eventually led to the success of 'Kolaveri'.