Honestly, there are to many variables to really be able to give you a concrete opinion on.
Like Ariakas said,.. someone who has complete disregard for the others feelings, is a massive red flag. Sometime`s that flag is born of jealousy. Sometimes its born of a good intuition. Either way, its a flag that needs paid attention too.
I have a ex-bf that my husband despises. To this day, he wants nothing to do with that person, and would happily never hear of him again. There was no way that relationship was ever going to fly. Rightly so.
Yet my husband and Ariakas get along really well. There is mutual respect, and friendship growing.
It boils down to circumstance, or it being person specific...as you already know.
Unfortunately there is no easy how-to booklet. You have to disect things and find out for yourself.