My DH is an only child. He’s quite highly strung. And in many ways the stereotypical example of an only child. When we got together he wasn't close to his parents, I'm not close to many, but I remember saying to him the way he spoke to his parents was horrific when they were trying to be helpful. A year ago they moved from
2 hours away from us to 5 mins away on foot so we’re a lot closer to them. Every time we see them or go over to theirs DH gets frustrated by something usually he disagrees with how they've done something (they have a habit of doing things randomly, or in a strange order of events) ultimately causing more friction for us. Inlaws are 80s and slowing down so a lot is falling to us currently. But he can’t voice irritations rationally, he just f’s and blinds and walks off.