You can be supportive of the person while criticizing something they did. Also, when you criticize, you can do it with arrogance or with kindness. As a signal

You can be supportive of the person while criticizing something they did. Also, when you criticize, you can do it with arrogance or with kindness. As a signal of good feedback, I would use the number of adjectives in your feedback. Instead of saying that something is bad, stupid, lazy, you can say that a function has too many lines or too many branches, or that 2 modules are too tightly coupled.