It helps to have a good sense of humour and patience. It might sound weird, but I've actually experienced some very positive things that I wouldn't have encountered as someone able bodied, some of those things are among my fondest memories. You get the other end of the spectrum as well, but I tend to disregard most of those, some people like the guy you mentioned parking in the disabled spot are just ignorant mostly and don't understand the ramifications of their actions.
You're right on the footpaths. Henry street up near the courthouse is terrible, the "ramps" to get up the gutters after crossing the road are impossible in a chair. It's improving though, Mulgoa Rd is great as well as parts of High St. The biggest drama is most disabled toilets. Most of the outside ones require a key, which is easy enough to get, the problem is reaching the key hole and then opening the 3 tonne door from a chair. I think the dickheads that design that shit assume that if you are in a chair you must have a carer with you to take care of that crap. I find that the hardest to work around. I rang the council a few years ago about fixing the big lip on my driveway as getting up it in a chair requires hitting it at speed and throwing your weight back to lift the front wheels. I've flipped it a few times and ended up flat on my back in the middle of the road with cars driving around me. I even said I'd pay for it, just I needed permission to do it. They said they would send the engineer out to have a look. I gave it a week and called to see what was happening and was told the engineer had been out and said it was fine as it was and met the standards. I asked them to send him back out and come and talk to me and show me how to navigate it in a chair, I even offered to give him a thousand dollars if he could get up it in a chair. They wouldn't do it. lol. A few weeks ago they came and put a footpath in, but still wouldnt do the driveway. With the footpath it's fine though as the ramps on to the street at the intersections are smooth as butter.