waiting sucks

Morning presentation just ended.. and it's 1.5 hours til i start my next presentation. I hate waiting. I know I am prepared for my presentation. Yet, every minute i look at my slides, i edit them. Add things, remove words, alter the animations.. i know there are countless ways to make it better, and it can never be perfect. But i think this waiting is killing me. Is it really worth the amount of effort i put into it? I know very clearly that other students that have presented before me didn't spend much time on their preparations. I can do the same. It's only 50% of the module, you say. It's only 30 minutes of standing there and presenting. Yet, i can't bring myself to stop improving on my slides, and to stop reading even more about the field so that i can tackle the Q&A with ease. It's a mental war.. in my own brain.. bah..