This is a great thread.
1. Inconsistent practice schedule without focused goals or time management
2. no warmup or technical exercises, except to practice scales or passages from the pieces. Wonder why I can't play fast scales?
3. No metronome work. Rubato to cheat the hard passages
4. Not scheduling lessons.
5. watching TV while "practicing"
6. playing on low couch instead of sitting on a proper chair.
Mind you, I am old enough and can admit this is my hobby, so I really don't get too stressed out about my slow progress. Some people have liked my recordings. I'm doing all right. I don't think I have to summit the mountain to enjoy the view.
Perhaps someone should start a thread on good habits we have. Just for balance.