The name "the most disliked" is a tall order, because it makes sense that if it's so disliked, how would many people know about it? Nonetheless....
Among orchestral players I associate with, there is one work that causes almost everyone to groan when it's programmed: the Franck symphony. Audiences may like it (although it seems to be less favored than it once was), conductors may revel in it, but the orchestra parts aren't all that rewarding to play.
For worst performance, there are so many to choose from, but the Marco Polo recording of the Furtwangler Piano Concerto is certainly a contender.