Opening the book…
Kind thoughts are cheap in your head and priceless out loud. We assume people know how we feel about them, but they usually don't. The good opinion you keep to yourself does no work in the world. I've noticed the compliments I almost said, then swallowed, are the ones I regret most.
When you notice something good about someone, say it before the moment passes. Name the specific thing: the sentence in their email, the way they handled a hard call. Tell them, not just the room. A short text counts. I try to treat the impulse to praise as a small obligation, not an option.
Kindness should be true, not automatic. Flattery to smooth a favor or dodge a hard conversation is a different thing, and people can feel the difference. Say the kind thing because it's real, not because it's useful.