Mostly PvP stuff with my Mind/Kin. Granted, it's PvP, so you gotta pull out all the stops to win (which I did very rarely, so, any dickishness was justified)
One time I was in the Recluse's Victory train station. I was melee'ing with a Brute (On a controller, yeah, I know, but Kin heals are melee range, so, yeah) when a Stalker comes up and tries to gank me. Well, it didn't work, and while still fending off the Brute, TK'd the Stalker into a corner and left him there indefinitely, recharging my stamina off the Brute. I held them both off for several minutes until a second Stalker swooped in and dropped my toggles. For what it's worth, I apologized to the first stalker, and he was able to laugh it off.
Another thing I liked doing was activating Repel and dive-bombing Masterminds, sending their henchmen flying everywhere. I called it "Bowling for Minions!"
A dickish thing I had happen TO me was the time I was running a costume contest. I announced the winners and tried giving them their prizes (Purple IOs), but a bunch of randoms were jumping all around the winners, so no matter how I tried adjusting my camera, people were in the way. So I called the winners into City Hall, and all these jerks followed. I managed to give out prizes to two of the winners, but the third winner claimed he didn't get anything. So I had to go to the auction house, buy a new recipe, salvage, and craft the damn thing, putting me quite a bit in the hole. I wondered at the time if the griefer and my contestant were in cahoots to get an extra purple, but other than reporting the guy who kept jumping in my way, I let it go.