In "Art of Cycling" the author says for most of us, being told the tricky bits to watch out for--railroad tracks, gravel, getting doored, etc--is not very effective. He says most of them (the bike messengers) had to experience each type of accident first hand. But after you've experienced it once, you will never have that type of fall again. You will know in your bones to avoid them!

You are a much better cyclist now having had this experience! (I'm trying to find a silver lining for you...)