Root canal by far.

I was discussing pain with a couple of friends, and I said root canal. One of the others said "The second worse pain I ever had was the time I was out hunting, and I had to poop. I dropped my pants and squatted down in a thicket. I didn't see the fox trap, but my plumbing tripped the damn trap and nearly cut my balls off."
Of course, I said, "If that was the SECOND worse pain you ever had, what the hell was the WORST."?

He said,


"When I came to the end of the chain."