A story of how screwed-up my moral standards are:

As I opened the door to the tunnel, a lady approached from the opposite direction. With one hand she held the harness of a guide dog, with the other she steadied herself on a walking cane. She seemed to be blind. I evaluated the situation, and held the door open for her as she passed through.

Now normally when a person approaches a door I've just opened, I open it all the way and hold it open for as long as my arm will reach the door, but I don't break stride. If they reach the door in time, fine. If not, they can still interrupt its swing shut with a good bodycheck, and I have done my duty as a good citizen by giving them an opportunity to pass through a door without dealing with the handle themselves.

Now for this blind, disabled lady with the guidedog, I held the door open. But I didn't hold it open because she was blind - blind people can generally manage doors, and I'd seen her pass this way before. I didn't hold it open because she was disabled - she had walking troubles but she wasn't frail (a frail person would probably have gotten a slightly longer door hold than a non-frail person). I didn't hold it open because her hands were full - it was a push door on her side.

No, I held it open because the guide dog was between her and the door, and I didn't know if the guide dog could bodycheck a door open, and I didn't want the beautiful doggie to get hurt. Ladies and gentlemen, my fucked up morals!