It belongs to human nature to hate those you have injured.

Hurting someone tends to make you like them less, which is the reverse of what you would expect. The mind will not sit comfortably with having done harm to a decent person, so it revises the person instead: they were difficult, they had it coming, they are not really owed anything. Resentment turns out to be cheaper than guilt.

If you have gone quietly cold on somebody for reasons you cannot quite lay out, check whether something you did came first. The order matters, because in that case the feeling is not information. Act against it once, with something small and generous, and see how quickly your view of them starts to move.