Well, what anime(s) were you disappointed in?
If it includes spoilers but it in the spoilers box, durr.
First, I'd say Togainu No Chi. Honestly, the drawing style was meh. But if you played the Visual Novel THEN watched the anime you would be disappointed beyond belief. Well it was probably partially because
Another would be Black Rock Shooter. I'm sure MANY of you would agree with me. I was very hyped up for this OVA only to be utterly disappointed. Sure, it had beautiful artwork and animation style. But the story just seemed... incomplete or rushed... I wish they would make a full anime of it.
Another one for sure would be Clannad. It's possible my least favorite anime. Why? Because it was so overrated. I was expecting an uber cryfest. Instead, I didn't cry at all. It seemed too... sappy... for me. It made me think.
Finally, I'd have to say K-On!! (Season 2). When people say they dislike this season, they never give an explanation (At least to me). So I will give one. I watched K-On! for the MUSIC. Oh, the music for the first series was AMAZING. I loved how the anime mostly revolved around the music. But then the second season came. I was so excited. But then got shot down.