For me I was thinking of two incidents I have experienced.
First, I stood in line with a family with a little girl in a wheelchair. My DS at the time was 5 and was asking me why she was in the chair. I explained that some people need the to get around and I didnt' know why she was in the chair and it is rude to ask. The mother overheard us and I guess thought we were questioning the use of the wheelchair and gruffly said to us "my daughter can't walk she is paralyzed." At which point my 5 year old asked what that meant, I explained it to him and then he asked the mom "if she can't move her legs then how come she keeps kicking my mom?" At which point the mom gave my DS a nasty look. I hushed my DS and said I would explain later. Then as we got to the front of the line I heard the little girl ask if she could please walk now she was tired of playing pretend.
Second, my family endured a group of ten teenagers that rotated through the wheelchair. At the first ride one young man was in the chair. As we exited BTMRR a new young man was riding while his buddy used him as a battering ram to shove through the crowd. My family tried heading in the other direction only to run into the same group in Tommorrowland where a young lady was now in the seat, screaming as someone raced her through the crowd to get to SM. These very rare but still frustrating expirences are what my rant is about no one else.