In Batman: Under the Red Hood, I'm brought before Black Mask, who asks if I can handle killing the Red Hood. To show him how stupid it is that he'd ask, I ask for a glass of water. I proceed to use it to kill one of Mask's mooks, then I take his gun and shoot the others.
In The Dark Knight, the way I mess with Harvey's already fragile psyche with my bedside lecture about "schemers" and how I'm merely an "agent of chaos". And then I put a gun in Harvey's hands, and finish my sales pitch with "And you know the thing about chaos? It's fair." The second Harvey breaks out the scarred two-sided coin, I've already won.
One time in Devil's Advocate, while I was awaiting my execution in Blackgate Prison, some fat thug named Tommy Mangles called me Whitey and threatened to murder me. I asked if I should apologize, but he insisted on killing me, saying, "'Sorry' don't walk the dog, Whitey." That's when I pulled off a Moment of Awesome that started bordering on Nightmare Fuel by attacking him in self-defense, starting off with a Groin Attack:
"Really? Well, what if I was really sorry? Would that make a— difference? Would that satisfy you? [I pull off my shoe and start beating him to a bloody pulp with it like a maniac...] If I was really... really... REALLY...REALLY... REALLY... SORRY? [...right before the guards restrain me] WELL, I'M NOT!"
Here's another Moment of Awesome that borders on Nightmare Fuel in Emperor Joker: I tricked Mr. Mxy into accidentally granting me his Reality Warping powers, turning me into a supreme being withPHENOMENAL COSMIC POWERS! With these powers of mine, I could turn the entire world into my own version of it, eat up all those Chinamen, and do the one thing that fewer of my past incarnations have done: kill the Bat and everyone associated with him (well, except Supes, of course), repeatedly, day after day, in all my creative, graphic, bloody and horrible ways! If that wasn't enough, I would even turn dear little Harl' into a constellation and DESTROY THE WHOLE DAMN UNIVERSE! Oooh, I bet you're quivering and shaking in your boots at one of my best Moments of Awesome yet!
Same goes for Batman: The Brave and the Bold's animated incarnation of the comic book; but swap out Mr. Kltpzyxm with the pesky Bat-Mite; have me mold Gotham (instead of the world) into my own likeness, with less deadly results; tone my entire plot down with a few things: setting up Death Traps that are more comedic and less heinous; repeatedly killing only the Bat (mostly offscreen, actually) and then reviving him with a snap of my fingers in a few seconds, for hours instead of days; sparing the little Bat-Munchkin by turning him into a B:TAS Harley incarnation of him and then forcing him to watch me play more games with Batsy with my newfangled powers; turning my dear Harley into a mutesilent film actress instead of a constellation; and attempting to make the Bat-Freak into an insane victim of drooling, mindless foppery instead of blowing up the entire universe — and you get a Moment of Awesome that's pretty much less Nightmare Fuel and more Funny Moment. What a show!