I know I won't make that mistake again!
And that's a very important learning tool - the screw up! Happily, nearly all screw ups amount to nothing more than a slightly less ideal or safe condition, and a learning opportunity. I can think back to hundreds of my screw ups while flying (and a few while riding right seat), and what I learned from them. What I learned stuck, as the screw up was memorable. The key is to put your faith in the aircraft itself, and the competence of your instructor in allowing you to screw up enough that you learn from it, without it actually being unsafe! You will be amazed at what the plane can tolerate in terms of errant operation, and you still get away with it. That's not a suggestion that you should try, but don't worry about imperfection either.