Years back when I was just a newbie kayaker I had difficulty hitting my rolls. I felt I never had enough time to completely set up to properly execute the roll. I panicked and swam everytime. Then a friend noticed that every time I came out of my boat I was choking and coughing up water. He pointed out that we as humans can't breath under water (da) and suggested I hold my breath. Great advice, I haven't missed a a roll since.