It would probably have cost you only 10 or 20 bucks to get a bike shop mechanic to take it off for you.

If you do insist on beating yourself up, bash the left side of your head with your left hand.... that way you remember that the left pedal is a left handed thread. (just don't bash yourself hard enough to cause memory loss, that would defeat the purpose.)

Pedals always tighten toward the front of the bike and losten toward the back. Both sides. A simple rule to keep in mind. Saves lots of knuckles.

Also, bottom brackets tighten toward the back and loosen toward the front. Remember both rules and your knuckles will thank you.

Is that looking from above or below (i.e. when you "flip" the bike)?

Both... if you think about it.

Edit: I guess it depends on whether you put the wrench above or below the axis of the threaded object you are tightening, or something like that... awww nevermind

OK, OK, *here's* the rule:

If the bike is upright, pedals tighten toward the front and loosen toward the back, and bottom brackets tighten toward the back and loosen toward the front. If the bike is upside down, pedals tighten toward the back and loosen toward the front, and bottom brackets tighten toward the front and loosen toward the back. If they're English-style bottom brackets, that is. Your knuckles will thank you for remembering this rule!