Maybe the delay(10) which delays your main loop for 10ms whenever there's serial data. Depends on your serial traffic, but I don't see anything else that would be as obvious.
BTW: While PaulS is kinda talking down to you, you're still the one asking for help and even though he's not helping you with the question you asked, he still gave you some valuable advice.
So if you don't want to discourage other people to help you, maybe show a bit less attitude?