I guess my definition of "Trolling" and TC's are different. By my standards, I would have gone with the middle ground of "Mood dependent" and "How much the other person deserves it".
Trolling to me is going out of your way to mess with or embarrass the other player(s), but NOT to the extent of being a complete ass or making it breaking the game/ruining fun for other people. Leading people into a corner to make themself look dumb in the chat (Through casual/completely joking conversation).
Or in say, an FPS, spending a few extra minutes of my time to single them out and kill them in a less-than-typical way (Examples being: Tracking a pesky sniper down and repair tooling them, or leaving a claymore behind them to kill them later, etc.)..
It's dumb to make the game unfun for others just because you're PO'd, just stop playing if it comes to that point. I like to screw around and catch people off guard in games, but usually not to the extent of being a jerk.