My ex's parents hated me from day 1 . Her dad in particular DESPISED me , her mom wasn't so bad (she was just very whupped by the father) . I tried my best to get along with him until he vaguely threatened to shoot me once , after that , I lost all respect for him (which I had very little to begin with).
I'm glad I got out of that relationship (my ex turned really insane after she cheated on me).
My current gf is the love of my life , and her parents are cool too (both cops) , and we get along just fine (her sister is fine too , though sometimes she can get quite annoying).