I can still remember the exact moment back in 2002 or 2003 where I realized just how much than me better Joe Tall was. We were having a cigarette near the Foxwoods poker room and he reviewed the action on a few hands we'd just played in a 20/40 game, and he remembered them in more detail than me, but he also processed the detail differently to emphasize different aspects of my game.
I was a winning player but after that night I stopped playing for a month, did nothing but study books, analyze hands and sessions, and grind out math to see if some of my assumptions about lines against various hand ranges were correct.
After that I got a lot better, jumped limits, and ended up meeting DeathDonkey in a 100/200 game at Commerce and again realized I was outclassed.
I'd say I owe them a debt of gratitude, but I'm pretty sure I already paid it at the tables.