So I'm typing an e-mail today, and go to send it. Except that I'm typing it in Mail and I normally use Notes, so I mistakenly press "esc" (which is what I use in Notes). To my surprise, I get a list of words that could be substituted for the word I had last typed (an example is shown below). I played with it for a minute, testing different words (I have never seen this before), and then suddenly the "trick" didn't work. However, I created a new message and suddenly it worked again. I couldn't see this documented anywhere, nor could I figure out why it stopped at some point. I thought this was an interesting feature, but one I'd never heard of. Anyone else know something about this?