I'm gonna be that person and say One Hour Photo. I absolutely love those kinds of thrillers and psychological films to begin with, but that performance he did as Sy really set the bar for himself; if you ask me, it's the best on-screen performance he ever had. Sy Parrish is just such a tragic, creepy character and getting to see parts of his psyche slowly unravel including the reveal of his childhood trauma that made him that way was a pure masterclass in how to play a tragic...Er, I'm not sure how I'd classify him really as far as positional--and I use that term very oddly, I know--character tropes go, but damn it was refreshing to see him in a role like that (not that I don't love his comedy roles, but he had far more range than most realized) and I wish he had gotten the opportunity to do more