unusual incident at McDonalds

Well, I had an unusual incident at a local McDonalds. I was taking my ex home from her 2nd job with my daughter in tow, when she asked if she could pick something up. I had no objection, so we went. I was waiting in the car with my daughter while she went in to get her stuff. While I was waiting, this young man came out, and he had a "wet floor" sign under his jacket, and he started to walk away. I did something totally out of character for me. I got out of the car, and asked him what he was doing. I basically shamed him into returning the sign. I have no idea what got into me to do that, or what it means, but there you go.