One of the tenets of my philosophy is to be unabashedly clear with my friends. I don’t “like my friends for their faults”. I like them for their inner selves, and point out the faults I see.
Sometimes, this can backfire. Instead of helping them, you shut them down during their moment of vulnerability. It happens when I speak in absolutes. It comes as a surprise, and does not accomplish anything.
This is a subtle reminder for myself, to remember how important the delivery is. Keep the other person in mind, empathize, and say it well.