In high school I read this poem, it went something like this : "after a while, you realise the difference between falling in love and.... " ... i forget the lines after that.
Now, I realise, that after a while, you learn the difference between spending time with people you like and enjoy company with, and spending time and just wasting time with people you don't really know.
When we are young we just hang out for the sake of being seen at a certain place, with the certain crowd. Etcetera. But as we get older, we realise that we actually don't just go out to spend money and time with people we don't care about. We go out because we want to share our time, a bit of ourselves with people that matter.
There is a difference between spending time and sharing our time. We realise this as we grow older.