While I wouldn't use a disabled parking spot, there are some exceptions from social norms that I allow myself:
- segregating trash (keeping an apartament clean and organised is crazy difficult by itself, and I still learn to put things into trash after using, at the age of 36)
- getting a sitting space in a crowded bus, even if there are old people around
As for the disabled parking spots, when I was ~25y.o., I had a knee issue for half a year. I didn't limp much, but every single step was painful and difficult. It was just half a year, and I didn't bother to get a disabled license plate, but still fully deserved to use the spots.
Since that time I always have doubt whether to point out to someone that they took a disabled parking spot. The way I handle it now is by asking someone who leaves a car, who doesn't look disabled, if they need some help (instead of pointing out that they are assholes). If they are indeed disabled, they won't mind, if they aren't - they feel like assholes :)