3. Bad timing
Don't begin a life-changing conversation when he's obviously very stressed. And don't utter the ominous phrase, "We need to talk." He'll think he's in big trouble. A gentler, more effective approach is, "Later on tonight or maybe tomorrow I want to have a conversation. It's not a big deal and it will only take a few minutes."
4. Tough tonality
He gets your displeasure, not the reason for it when you bark at him like at a puppy who missed the newspaper. Or when you sound like a teacher chastising a wayward pupil. Or when you are condescending and bitchy. Or when...
5. Lack of appreciation
You notice when he messes up but rarely mention when he gets it right. Repeat after me: Compliment, don't castrate.