It's funny how your expectations of a show can wildly influence your enjoyment of it. I once watched about the first 10 minutes of the movie version of "Thoroughly Modern Milly" on television and was thoroughly bored. So when we ended up with season tickets that included the musical at the Ahmanson, I wasn't expecting much and thoroughly loved it! It's probably one of the best musicals I've seen, but maybe I just feel that way because my expectations were so low.
Conversely, I had been playing the CD of "Wicked" in my car and singing along (badly) and knew all the words for so many months, and had the musical so built up in my mind, that when I finally saw it at the Pantages, I was actually disappointed. I mean it was very enjoyable, but it didn't exactly rock my world like the CD did.
By far, the best one-man play I ever saw was "Fully Committed" with Jason Graae. He was his usual incredible self. It was one of those shows that was so funny that my face hurt when I left the theater from smiling and laughing so much. I really wanted to see it again, but we saw it on the last night. If nothing else, even if you didn't like the show, you had to be in awe of someone that can memorize ALL the lines of a 90-minute show.