I found my ex-partner's arrogance and selfishness difficult to handle from day one. And, silly me, tried to change them ... and it seemed that for about ten years it worked. They came back with a vengeance last autumn though, and it was too much.
I found his extreme unpunctuality infuriating too. I'm a bit of a late person - not good at being exactly on time, and usually 10 minutes or so late ... but he took it to a different stratosphere!
So come on, are these traits - and what other traits are - unworthy of loving acceptance?