The first D&D episode is one of my least favorites. It had some great moments, but it's the only episode from the first three seasons that I haven't watched more than once. I just can't stand Pierce in that episode. He was at his all time worst. It just makes me angry to see such a horrible person and for others to sit by and let him be that way makes it all the worst. Annie's seduction scene is one of the highlights of the series, but it's impossible for me to get that far in repeat viewings.
Overall this season has been the worst of the five in my opinion. I know a lot of people aren't going to agree just because Dan Harmon wasn't around last season, but at least then the writing and characters were consistent with previous seasons. If you ignore the credits most of those episodes stand up with the rest of the series, not so much for this year.
Episode 10 was the first time we saw the Dean being anything like he was in previous seasons. He's been a complete disappointment this year. Has Jim Rash not had time to make it to wardrobe and learn more than one or two lines the rest of this season? Chang hasn't had much of a role either.
And what does Dan Harmon have against Yvette Nicole Brown this year? Has she had a significant story-line at all? In this episode she was gone within the first five minutes. In GI Jeff she basically repeated one line over and over again. If Harmon keeps this up I'm guessing she won't stay around at all.
The fact that no one is really attending classes anymore also hurts the show. Kind of pointless to be at a Community College and not go to class. Greendale has some great educational opportunities, Who's The Boss, Sailing, Pottery, Ladders, History of Ice Cream. None of that has been around this year. It's just sad.