Very first week of commuting, with crappy panniers (and a just as crappy cyclist at the helm). Jostled the panniers too much as I was pushing off from the intersection, one of the rack hooks on the panniers comes off.

That pannier catches a spoke, pulling nearly the entire pannier bag into the (very small) space between my rack and my rear wheel. This causes my speed to rapidly decrease, until I find myself in the middle of an intersection with a bike that suddenly won't roll.

I am sure that all the front-row motorists got a good chuckle at the stream of profanity that came out of my mouth, while I very quickly shouldered the bike and ran across the rest of the intersection.

Yep. I got Ortliebs shortly thereafter.