You can also just sit there and wait until everyone you ever bonded with gets diagnosed. It's fun to listen to them explaining how the process went and slowly coming to some realizations about yourself.
Made me (diagnosed with ADHD-I) chuckle, that could definitely be me. Usually one of these:
Forget the appointment altogether.
Remember appointment, be unable to do anything beforehand, find something to distract me of that impending appointment dread, forget the appointment that initially took up my entire attention span.