The phrase, "Don't judge a book by its cover," may be old, but it's still teaching lessons to this day. When people can’t see your disabilities, sometimes they make snap judgments and do cruel things. Nikki Waller and her sons found this out the hard way when they went to a local Wal-Mart in Pennsylvania.

Waller parked in a handicapped spot close to the store. She has a handicap tag for her car because her 7-year-old son Alex has juvenile arthritis with myalgia and hypermobility disorder, according to The Mighty. This painful condition makes it difficult for him to walk.

The fact that Waller and her sons appeared able-bodied must’ve set an unseen bystander off because when Waller came out of the store, she found a rude note on her windshield. It said, "Reserved parking @*#hole Did your welfare check come today?" according to WTAE.

At first, Waller was amused by the note, according to WTAE. Then as she thought about it more, she was saddened and then angered.

In the end, Waller decided to use the note as a teaching tool. She showed it to her sons and posted on Facebook about the incident so that people will think twice before they judge people based on what they see. "I put the post out there, I didn't ask people to share it, I'm not calling out the person who wrote this but it's just an education for the community as to this exists, there are people with invisible diseases and illnesses who do need handicap parking. Just because 20 feet away they don't look like they do they may have something going on that you don't even know about," Waller told WTAE.