Psychotherapist Alice Miller once said that you can tell whether it is appropriate to criticize someone by paying attention to how you feel when you do it.
“If, when criticizing a friend or someone around you, you feel a sense of pain, then it’s okay to proceed. But if you feel even the slightest pleasure, that’s when you should hold your tongue.”
Feeling pleasure while criticizing is not true criticism—it is condemnation. Such an attitude often stems from pride, from viewing yourself as superior to the other person. If you do not stop at that very moment, it will not be the other person’s faults that are exposed, but your own character that ends up being criticized.