I have to say Cadets 2008.
I personally liked the show and I just loved the ending that I saw in Orlando and Atlanta, the ending with the smiley face . However when I saw it during Big, Loud, and Live, I was really irritated that they took out that powerfully emotional statement of their show just so they could play loud and end with a plain and dead ending.
Also from 2008 the Bluecoats. I was a little bit disappointed when they made the brass stop counting at the end.