Planet bike rear light. Light body separated from the base. Grr. Taped it together and purchased other brand lights from there on out.

Sunlight panniers. Had issues with one bouncing off. Very bad. Started utilizing auxiliary bungee cord, but gave up on rear portage and went with front rack and bag on commuter bike. If I was in some situation where a rear rack and panniers were again necessary, I'd go with upgraded gear, not budget stuff.