Well, I know I'm a day or so late getting this out but seeing this got me thinking a bit like you do.
For instance, just who is your friend, how would you separate them from say just the people you work or go college with or say family members?
When it comes to to it even, how do we show our appreciation of what that thing - friendship - is, such as the time we spend with them, the extent to which we go out of our way to help one another?
Have we wished each other a nice day?
It might be me but I think these things do matter no matter what differences there maybe between us and maybe all of us might benefit from thinking more about what we can do for each other as friends.