The door of the unit is always open, and it is always banging. I want to write a slogan, which reminds people who go out to close the door without hurting others' self-esteem. It is a bit humorous.

I hope I can help you. My first thought is: Please close your quality door. Or please close the door of your quality. There is also the quality of people will close the door behind them. After that, put a smiling face on it. They are embarrassed not to close the door behind them. Anyway, I did it in my previous company in a similar situation, and it is still useful. Remember to put a funny icon on it, preferably related to this sentence. If it doesn't work, it will be a lovely picture.