I'm doing the Elsweyr main story with one of my 5 mains right now (a Pet Sorc) and while i'm running through the zone i have several skills on my back bar that i'm leveling up.
At the moment that's a bunch of Undaunted skills, one of which is Inner Fire.

I come across a dragon fight and join in, laying down some nice AOE with my front bar and when the dragon gets down to about 1 million health i switch to the back bar to use the XP from the dragon to level up the skills on that bar.

As you probably guessed by now while i'm standing on the side just out of reach of one of the wings i accidentally hit Inner Fire and the dragon turns and looks straight at me.
Gotta admit, that was pretty epic right then and there.

Thankfully it died a moment later before it got a chance to focus on my squishy light armor Sorc ...