I guess I never really noticed that, but then I always think I'm a good judge of character. I choose who I want to be kind and friendly too. If I sense they're a butt head, I just wave them off and move on. Life is just too short and there are just way too many nice places and people to waste my time and effort on butt heads.
You are right though, there are a few parks that are full of butt heads that are very clicky once you stay long enough to get into their "inner" circle (so as to hear them back stab others in the park.)
Honestly, I feel sorry for them. This is supposedly their golden years, and they're wasting them on things that we grew out of in High School.
As the younger kids say "haters, just want to hate." Just like water on a ducks back, let it roll off.