Q&D is a good one (meaning bad one). That movie was horrific.
For me, I'd have to say Punch Drunk Love with Adam Sandler. I'm not a huge Sandler fan but I expect to get at least a few cheap laughs from his movies. This was him trying to do a dramatic role. My wife and I knew someone who saw it and raved about it. So, we saw it. Half way through I was squirming. And, when it ended people applauded! I looked at my wife and said "I guess they are really happy it's finally over".
Btw, a movie that had a good cast, and that I expected to be horrible but surprised me was Airheads also with Sandler, as well as Brendan Frasier, Steve Buscemi, Chris Farley, Michael Mckean, Judd Nelso and Ernie Hudson. A few other names in in too. It has a fantastic cast but it just looked so incredibly stupid I passed on it when it came out. I caught it on cable a few years later and it's actually hilarious. The basic premise is a bunch of wannabe rock musicians take over a radio station so they can get their music played, and wackiness ensues. It really should be a stupid movie but the cast is so good they pull it off. Worth watching.
Btw, another Costner movie that is good despite the horrible acting of a few of the characters is Silverado. Basically, if you just put the TV on mute any time Rosanna Arquette is going to say a line, you should be ok.