Why do people do this?

So 2 weekends ago I went skiing with my friend. We were in the park and my friend falls. His skis are completely out of the way and not in front of any features. Then out of nowhere, some idiot on a snowboard comes flying straight at my friends skis and whams right into them. The guy didn't even look back. A few hours later, I fall. Same thing with me, my skis are completely of the way. Then some skier comes at my skis and smashes into mine 2 times harder than my friends. The guy then just screams what the f*** at me like it was my fault. That pissed me of pretty bad, especially since it left a pretty big ding on my skis. Rant over. And just so you know, this is my 1st post, nice to meet everyone lol.