The wheels on my desk chair don't roll very well.  I figured something of the kids had gotten stuck in there (ribbons, papers or other crafty stuff... who knows).  But when I flipped my chair over that wasn't the case.  The wheels were completely wrapped in hair.  I guess I should have known.  It's got to go somewhere.  And of course if I'm sitting at my desk, pulling hair, and letting them drop to the floor... of course they're going to get tangled up in my wheels.  I guess it's just bizarre to see evidence of your pulling, evidence besides thinning and bald patches.