Also, what really irritates me, and this is something even the most popular and recognized authors do, is using fantasy as crutch. Just because you can make the rules doesn't mean you should use the genre as your instant-plot-device machine. I mean yes, of course your plot devices are extraordinary when you write fantasy, that's the whole point, but it should be more about establishing new rules (at least to yourself, if you want to keep the reader wondering) not churning out deus ex machina every time you write yourself into a corner.
This annoys me as well. What's worse though, in my opinion, is when people who don't read fantasy use this as an argument as of why fantasy sucks (or is just plain bad), since this is common among not-so-good authors everywhere on the genre-spectrum.
speed-edit: The use of deus ex machina's (machinae?), that is. Not using the setting as an excuse for it.