Last week on my squat day I was unable to squat because my knee was killing me. I was so furious that I pulled instead. I had just pulled very heavy 4days earlier, but I was furious and set two PR's raw. Luckily I pull very stiff-legged anyway, so my knee didn't bother me deadlifting.
505x2 w/belt PR(crazy grinder)
405x8 deadlift w/no belt PR