Siblings
At least remotely (text, social media, etc), my brother ALWAYS has to one-up me. If I share a picture he has to share at least one similar one. If I have a story or anecdote at work, he will always follow up with a "better" one. There's never a "that was really funny" or "that was really neat" or "thank you for sharing.
It's gotten to the point where if he's on a thread or in the same group, I don't share.