Especially on drunken Saturday night rides where bikes end up leaning on each other or piled on the ground, it's a good idea to take a moment to pick up each end of the bike and whap the tire hard in the direction of the drop-out to double-check that the Q.R. or bolts are set correctly. It only takes a second and could save you a lot of trouble. Bolts especially make me nervous as you can't see that they've come loose. Now if I could only remember to take my own advice...