There was a poorly implemented customer support system that I worked with once that due to the way the app worked, support could run a query that would essentially scan the entire database, predictably it'd hit a proxy timeout. So what happened instead was they would open 10+ tabs doing the exact same query hoping one would get lucky and succeed, and we had to figure out why our database was getting ddos'd. Trying to explain that they were actually making the issue worse with the workaround was very painful, saying stuff like "well what did you change, it was working fine for months."