Sometimes you play the hole, sometimes the hole plays you. Sometimes you just have to turn over and smell the fishes. A wave is just a wave, but holes suck. It's hard to roll with half a paddle. Whatever can go wrong, will go wrong.
Murphy lives in rapids.
The willingness of a paddler to run a nasty drop is directly proportional to the number of cameras present. Beginners will always lean upstream at the least opportune moment. A rapid is rated as class III plus the number of times you have to take a leak while scouting.