I'm more of an au naturel climber. Buildings tend just to be repetition, doing the same move, over and over again. It's a primitive response to all this complexity around you. You take it down to the most basic level, against this hi-tech domination of mankind. And it's a different experience from a crag.
People are outraged by seeing somebody trying to climb something.
Sometimes it's not outrage. One Sunday morning he was on his way at dawn to a job in Gants Hill when he spotted a block of flats whose bricks protruded about half an inch all the way up. It formed a diamond shape up the sides of the flat. So I started up. It was about 6a crimping on the edges.