I've seen Chazz tribute Ojama Knight to summon Armed Dragon LV5, thus freeing my monster zones.....and he didn't even use AD LV5's effect, even though he could.
And after that Chazz just go straight to End Phase, he didn't even attack, again, even though he could.
Another time, I saw Jesse going into Battle Phase without any face-up Attack Position monster on his field (I clearly hear him say "Battle!"). Needless to say, he then immediately goes to End Phase. That was the first time I see an AI do that, they usually skip Battle Phase in that situation.
The partner AI is garbage too. I’ve had to turn on manual duel for the Yugi cup because he doesn’t seem to ever use my cards properly.
I think the most infuriating moment was when the had a Silent Swordsman out and a facedown SSS. No enemy monsters left, no back row, lifepoints wide open. Yugi attacks leaving them with *exactly* 1500 LPs, then used SSS while ending his turn.
I had to duel lv20 Mai/Tea instead of lv40 the first time I went through the DM cup, because the Yami Yugi partner AI is so bad, I lost three times in a row against lv40 Mai/Tea.
It truly is. Between his constant need to do *anything* to summon DM and always having your monsters get banished, that matchup was truly the worst first time around. The only other deck to give me similar difficulty with the mandatory AI was the crystal beast deck because he always summoned that 4000 attack monster on the first turn you attacked.