I'm usually not very patient, mostly with so called 'normal' people, because I expect that they could be/move/do faster then they sometimes do.
If a person is slow because old age, injuries/illness or invalidity, I have more patience, because they can't be/move faster. There are situations where I offer to help them, if I see they have problems, that I can easily solve. I even got a lot of thanks for doing that, because many sane/healthy people are just afraid of asking to help, but not afraid at acting impatiently and ill-mannered at them.
Added: I had some accidents and while beeing slow with casks at foot and hand, I understand the problem of not beeing able to do like one is used to.