I know so many people who don't keep in contact with high school friends, but still meet up with college friends from time to time. There's just something special about throwing a bunch of people of the same age into this melting pot that they chose to be thrown in to that creates these social networks that last a lifetime. Military friendships also seem to mirror this same effect
Well, it's also typically the last place you get the opportunity to make a whole bunch of friendships before heading out into the adult world where it requires much more effort.
