I work with a woman who is legally 80% disabled due to issues with her neck, both shoulders, and both knees. Looking at her you’d think she was not disabled. She looks perfectly fine. I know another person who was in a head on collision. Both heels were pulverized, the heart was damaged enough he suffered congestive heart failure and some traumatic brain injury. If you saw him now, his heels have healed well enough that he is able to walk well most days. His heart is pumping much better and his thinking is clearer but there are days he gets frustrated because his brain isn’t working quite right.
If you looked at either person as they stepped out of their cars parked in handicapped parking, you might call the police to report them for illegally parking. Even with the permanent plates, you might not believe they qualified.
Both of these people are legally handicapped yet they may not look it. They are members of the group with invisible disabilities, disabilities you do not see. Sometimes we have to accept the disabilities even though we cannot “see” them.
Do not swear at them thinking them liars. Do not key their cars in protest because you think them faking. Do not push them because you could hurt them. Just because the disability is not visible, it does not mean they are not.