At a particular time and place, and one of them texts the group to say they will be ten minutes late do you: make more of an effort to be on time so that the third person is not waiting alone (I’m reasonable), or turn up fifteen minutes late to make sure none of your time is wasted (I’m not reasonable)?
Seems such a small thing, but I just realised while waiting that I knew exactly how my friend’s automatic calculations would go, and how in so many small and large ways I would automatically show consideration towards her that is not reciprocated. Thinking of stepping back a bit.