Yes, as redshrike says: the proper etiquette response is something like? "Oh? Oh, I'm sorry." "I'm sorry it feels that way" is the full text, but these days that one is often a) recognized as a dodge and b) followed up with more awkward questions.
Either way, family is likely to suggest you "do something nice" to the wretched creature, at which point you look confused and say, "Well, golly, I thought I *was* being nice to it. I don't rightly know what I *could* do to be nice to it: I don't know it very well, apparently."
And change the subject, or offer the it some software from work, which is "nice" enough to get relatives off one's back, and doesn't really ask much of you at all. (No time spent together, for instance.) If some "face time" is suggested, you look uncomfortable and say "We just don't seem to have much in common, and I'd be afraid I might inadvertently offend it again."
Poison is only suggested in extreme cases, as a death in the family usually means funerals and even more having to be hypocritically nice to people one doesn't really like.