Is it me, or are people getting meaner & meaner?

I've had 4 almost lifelong friends (only 2 of them knew each other) stab me in the back recently, in one form or another. All entirely unrelated issues & all completely undeserved (i.e. I just found out my friend of 19 years was sleeping with my ex fiance while he & I were together- she told me about it & didn't even seem bothered). Why did she do it? Because, according to her, it was "just sex". This is just one example, but you get the idea. I've talked to a couple of people about what's been going on, & they all seem to agree that people are getting meaner & more cruel to each other by the day. This seems to be getting worse as I get older (I'm 33). Am I crazy or is society as a whole becoming this way?