I guess you could read a lot of people's answers in the current "What rides do you avoid" thread to get the answer to this question but I'll elaborate on mine...
While I don't rate many of the Disney restaurtants, there's not many that I'd say were particularly bad - I just find them pretty average. The only obvious exception (for me) is the Rainforest Cafe at DTD where we have never failed to have poor service
and average food. We won't eat there again now.
As far as rides are concerned, I took an instant dislike to the Tikki Room. Awful place, bad music, bad script and tacky wooden birds that are so unlifelike it's not true. The refurb and new management did nothing to improve the attraction. I think a Tikki Fire is needed here!
To a lesser degree (and while I'm on a whinge-roll) I don't particularly like the Mexican ride in Epcot although we end up doing it every trip (they made a poor ride worse with the ducks too in my view). My opinion of some of the other rides has also gone down simply as I've got bored of them. Most of the 3d films fall into his category, as does the Indy stunt show. The backstage tour and the stunt show at DHS as well as the Jungle Cruise are in danger of heading that way now too.
Just as well there's plenty of other stuff left that I love!