Special relativity is the girl you meet at the dorm party while you’re dating electrodynamics. You make out. It’s not really cheating because it’s not like you call her back. But you have a sneaking suspicion she knows electrodynamics and told her everything.
via Kottke
Statistical Mechanics: The large and severe matron who taught you in elementary school, ruler in hand to smack you if you got out of line.