Just thinking trains as I follow an interesting person's rides around Europe.. I think the absolute worst ride has to be the Class 142 Pacer. God that rattled and shook it's way around Manchester.
I think worst seat is a toss-up of airline seating on the Class 185 Pennine, the Class 390 Pendolino and on the Class 397 Civity.
They're all frankly shit for legroom (
#TallPersonProblems) but the Civity seats just don't feel comfortable to relax in on a long journey.