A good thing to mentally get you benching good for body building is the fact that you're not trying to bench the absolute most but rather develop your chest. Proper form with a weight you can handle is a hell of a lot more beneficial to getting a full chest compared to a sloppy lift where ur hips are so high off the bench that you can fit a medicine ball underneath you.

Another good thing to remeber when benching is to look to Arnold. Never once have you heard anyone said he did sooo much weight when benching and he has what many would consider the best chest of all time.