I know there are the obvious really big dealbreakers, like not being racist, sexist, homophobic, and so on, which should be aligned in a relationship.
But would it bother you if your own personal "smaller" values - I don't know, things like being empathetic, not placing importance on 'stuff' or in impressing others with your status or material success, honesty, helping others, etc. - weren't shared by your partner?