What's a game misplay/oversight you've seen in the anime? (I know there's some made due to story symbolism or they acknowledge it.) I'd say when Yusei fights Armstrong and he uses Call of the Haunted to summon The Kick Man (still less attack even with Axe of Despair instead of Tri-Horned Dragon).
What is the worst case of one deck paying for another deck's sins by taking a hit from the ban list?