I went to Chelsea 2013 in a wheelchair as my new feet weren't yet up to a day on crutches. Most people were incredibly kind and helpful about letting me get to the front to see gardens and displays both outside and in the floral marquee but some were really stupid and unpleasant. I also found most of the big gardens very difficult to see from wheelchair height and one had actually put up a bar fence at wheelchair eye height!
Negotiating the tube was an eye opener - plenty of stations with lifts but all still with some stairs to negotiate before getting to the platform. If I'd been a real invalid it would have been impossible.
Earlier on I went to a big building and renovation exhibition in Brussels and found most of the exhibits inaccessible because of narrow accesses or hard to negotiate bumps up where they had installed fancy flooring. Negotiating Antwerp on crutches in sleet and snow wasn't fun either with people rushing past and knocking me off balance.
Viewing the world at general bum height is an eye opener too but for other reasons!
I know old buildings can be hard to convert but all new and recent buildings designed for public access from offices to shops to museums, cafés, restaurants and so forth really need to take disabled access and toilets into account right from the start. Disability could happen to any of us on a temporary or permanent basis and is hard enough to cope with without unnecessary obstacles and lack of consideration from others.