Originally Posted by TWA Fan 1

The worst I ever had was not actually a jerk pax, it was on NW when the person who sat down next to me must have weighed at least 450 lbs.

His gelatinous and blubbery belly spilled over into my seat and was resting squarely on...my lap

It was warm and squirmy...I think there are few more horrible experiences to be had on an airplane...