When I was about six or seven years old, I went out to breakfast with my dad at a restaurant called 'Olympic Star'. I know it is either in or near Tinley Park, so maybe you have heard of it. I excused myself from the table to use the bathroom. I opened the squeaky door and went into the bathroom, and since there were only three stalls and all the doors were open, I knew no one was in the bathroom except for me.
I walked into one of the stalls and turned around and locked the door, and as soon as I did that, the door started to violently shake back and forth by itself, as if someone was trying to get in from the other side. I looked through the crack in the door, and all I saw was a transparent red color about 5 feet high, about where someone's shirt would have been, but I could see right through it!
Then, after the door stopped shaking, I heard a loud, prolonged sigh, as if someone was frustrated that they couldn't open the stall door. Suddenly, everything just stopped as if someone flipped a switch. No one had opened or closed the door leading into the bathroom the entire time I was in there, and if they did, I would have heard it. Plus, I would have been able to see the person's feet from the opening at the bottom of the stall door, but there weren't any feet to be seen! I immediately searched the bathroom to see if anybody really was in there, but there was no one. I find it very odd that a possible entity was angry because it couldn't open a door, when it could probably just walk right through it.
To this day, many years later, I still don't have a clue what happened in that bathroom, but something happened that I will never be able to explain.