I know that this is the sort of question you'd precisely expect from someone whose mental defenses were resisting the exercise, but it's still a valid possibility, prior probability ~1%: What if you suspect the person you're dealing with is actually a sociopath?

Learning to like a sociopath is actually extremely DANGEROUS---it opens you up to be exploited. Most people are not sociopaths of course, and if someone cuts you off in traffic it makes a lot more sense to attribute that to ordinary carelessness rather than extraordinary malice.

But in the particular case I'm thinking of, this acquaintance of mine has already destroyed the reputation of one of my friends, and accused me of perjury in an official university hearing. Once he called me up out of the blue in order to complain about my body odor. Meanwhile, he appears capable of lying without any effort---several times I've found out that things he said were untrue when at the time they seemed completely sincere. He has exactly the sort of superficial charm that high-functioning sociopaths do, and most people like him when they first see him. I even liked him at first, until I saw that he was deceiving and manipulating people.

All of this strikes me as sufficient evidence to conclude that there is a good chance (P ~ 60%?) that he is actually a sociopath, in which case learning to like him is exactly the wrong thing to do.