For me it has to be pissing off melees by HoPing the clothie they're beating on.
More specifically, when a Rogue thinks he's going to get a super free kill off that Lock from his stun locking and cloak. I drop by like a BOSS and HoP that Warlock. It's even more fun if you wait until the Rogue blows his CloS and the Lock is almost dead, like at 15%. I HoP and watch the Rogue rage as the Warlock proceeds to own his face. If it's up, I also drop a stun just for extra lawl factor.
I love it!