There were Riders I couldn't stand personality wise, but I do think most of the riders served some purpose, but here's a few that made me cringe/or blow up at the TV.
Femme: annoyed the crap outta me. Girl, that passive-agressive schtick is long gone. Read a book.
Delta: when donned by Mihara. Ok, I get it. He's the average Joe Schmo who just wants to stick his head in the sand and make believe all the baddies would go away, but seriously, you couldn't have found a whinier, pissier guy than him. For sake, that girl, (forgot her name) was a better Rider than you.
The Hoppers were unremarkable.
Chalice coupled with Amane: Hajime alone was great. Loved his character, but he'd turn into a putty without a brain around Amane. That annoyed me.
I haven't watched Den-O or finished Decade yet, but yeah.