So the 'never trust an elf' thing came from one of the early novels. But the sentiment behind it is easy to figure out. Elves are the 'beautiful people', same as the glitterati and other sorts today. A pretty face can open a helluvalot of doors, especially when you combine the fact that many elves work their way into wealth and influence (and don't get me started on the ones that have been hanging around since the last age of magic). Pretty people get a better break than ugly people in 90% of situations. You know it. I know it. We might not like it, but that's chip truth. And let's be honest, we resent the pretty people for having those breaks, not the least because we wish, on some level, we were them, no matter what we say. And when the pretty people get it in their head that they DESERVE more, just because they're pretty, that pisses some people off. When they have the ability to make it happen, that's even worse. And on top of it all, they have a life span conservatively estimated at several centuries, and will look pretty for damn near all of that time, well, that's just kicking them when they're down.