There are various things that I probably complain about, but the one thing that really bugs me is people being late or changing plans at the very last moment.
As someone who uses a wheelchair I am used to plan ahead and checking everything out in advance to make sure it is accessible, practical and safe for me to go there or do that.
Also be using public transport such as a train, or taxi and I have to book it in advance for wheelchair access.
Theatres & cinemas also have accessible spaces which ideally should be booked in advance this means it is much harder or riskier to be spontaneous. This is why I need to know plans in advance and for them to be stuck to.