"Damn you!" if I win a game or something a friend 
was competing for. 

Nowadays, strangers us stronger words like 
f****r, a*****e, god ****, etc if they are 
actually hostile. 

People frequently post similar messages on the 
forum, but most are simply to indicate they are 
frustrated, but not angry at the other person. 

It could be that this person is just being a 
overly familiar.