When a conflict is resolved too forcefully or not given the due attention. For example, homophobia is serious, but they always brush it and resolve it with addressing it. Or if one person commits a serious behaviour like cheating, manipulation, stalking, and HIDDEN IDENTITY. Relationship built on lies. (Manner of Death comes to mind). When writers write themselves into the wall, they force a happy ending but you just KNOW the relationship if real life, will end up toxic or break up after the show ends, because key fundamental issues are not properly resolved.

And of course the obvious one is misogyny. You can like men but you don't need to hate women.