When I was in college, I trained/worked in a gym owned by a guy who has competed several times in the World Strongest Man Competition. Yes, the one you see on TV. He was well known for his bench press, but had really good deadlifts and squats too. My freshman year, I got up to about 275 on bench and he changed my whole form and approach. Within a month, I was repping 275 for 3-4 reps. Tried 300 just to get a 300 lb bench, couldn't budge it. Two week later, I was opening up the gym and he came in. He put 315 on the bar and told me to try it. It went up fairly easy.
He told me he had the same problem at 600 lbs, so he just went past that amount and never tried it. First time he went over 600 he paused 635 unassisted. It was a mental thing.