I too cursed somethimes when such a thing happens. However go and look at real games and those players do some prety stupid things as well. You can only have control over yourself, when you have other people playing for you you'll have to live with it they make mistakes, it isn't funny when you se it, and you curse ofcourse, but it's part of the game.
If a player makes you angry enough times you can sell him and try to get a less stupid fellow.
I think these stupid actions depend on the experience level of the players.
But yeah they can be realy annoying. That's why I like them! ;)
They are not your friends; they dispise you. I am the only one you can count on. Trust me.