I'm not one to have inspirational little notes on my mirror (YOU CAN DO IT! THIS IS YOUR DAY!).
I do come across a few quotes, often by Ralph Waldo Emerson (whose work I have read none of) and I like them. If they're attached to some cute picture I occasionally print them out and stick them on my craft room walls, where my PC is, for inspiration. (I should note that I found my own pictures to put the quotes on rather than stealing someone elses work).
Here are a few: