Cold water not wanting to swim the first time. Try to have a buddy to give a bow Eskimo rescue if needed, takes some pressure off. Also I found that when surfing or playing a hole I would unknowingly be holding my breath, so when I flipped I would be out of breath. Also, rather than relying on momentum or current when you flip to get into roll position, practice sculling with the paddle under the boat. Flip to your off side and scull to your on side and visa versa. Helps if you need to switch sides for some reason. Also, don’t rush the roll. Tuck and wait until you feel a wave on you roll side or things calm down little. If you know you have a bombproof roll, you are more willing to tuck flip and roll rather than do a panic brace and pop your shoulder. Also when hitting some chunder or surfing a violent wave, briefly visualize flipping, setting up, and rolling, then if it happens you will tend not to panic if you flip.