With almost any show that has a large cast, there's always a character or two (or more) that tempts me to fast forward. With DS, there's the occasional character and also the plotline. If a plotline is really good or I'm really interested in it, I can tolerate characters that I find irritating.
My FF picks:
Hallie Stokes and the summer 1970 plot. Sitting through some of those scenes with her and David was excrutiating. Never mind FF, I skipped some of those episodes entirely - and probably will never go back and watch them.
Phillip and Megan Todd at the Antique shop, and later Megan and Phillip with all the little Jebs. The temptation to FF was
painfully strong.
Adam/Eve/Nicholas - I'm not much of a fan of the Adam storyline, but I was never tempted to FF when characters like Barnabas, Carolyn, Elizabeth, Vicki or Roger were on screen. But the scenes with Adam and Nicholas, and Eve and Nicholas, and all three of them together - my finger was on the FF button, getting ready to make use of it.
Other characters that irritate me and make think of the FF button - Jeff/Dirk/Ned, Bruno, Roxanne, Sabrina and Amanda. But since Roxanne is often onscreen with Barnabas, FF-ing is just not possible. It's the same with Amanda (because of Quentin) and sometimes Jeff (because of Vicki). Unfortunately.