alt Hacker NewsMe calling someone uncool would be rather hypocritical in afraid! I've done some interesting things, cool even, but that doesn't necessarily make conversation with me interesting/cool! I'll go with letting them know I find it dickish and perhaps even a tad offensive.
Counterpoint: if you're uncool yourself, you might be uncool enough to call out uncoolness, from a "game recognizes game" point of view