Celebrities are caught by stardom all around. Each and every moment of theirs is tracked by the media and fans and so they should remain extra careful in whatever they do. That’s actually what costs for their fame.
If you do some good deed then you come on to the front page, get appreciated and the news is forgotten in a day or two. But if you did something that humiliated you publically then it’s going to etch in the public memory forever and no matter what you do it is not going to erase off.
Some celebs have had a first hand experience in this. Check out the list.