A good rule for those in leadership, or just for people who want to get along with others in general, is "be at least twice as willing to complement as you are to criticize."
Sometimes people need to be told when they've failed. They also need to be told when they've succeeded. In the context of software engineering, the best team leads are the ones who actually take the time to understand the code in your PR and let you know if there's something specific that they like.
That's how you know they're doing their job instead of just speeding through the code review looking for low hanging fruit mistakes.