What are some cards you'd normally run in your deck, but don't because of your tag partner misusing it?
I find that partners waste Compulsory. Worse though, they have no idea when to waste Solemn Judgment. Mine just used it up on a 400 attack normal monster.
On the other hand, it is ridiculous that they WON'T activate killing trap cards if you currently only have a stronger monster out when they summon something, even if that something is a Brionac or Chaos Sorcerer.