Yeah, didn't they feel that Pop was unfinished and rushed, and tried to rectify that with the Best Of 1990-2000 remixes? But I would think playing them live would help them get over that feeling if the reception was warm enough- but then again, they did have some poor performances of Pop songs (such as Staring At The Sun) when the tour first started, since they hadn't rehearsed them enough. Maybe even after mastering the songs live (they had to have, since the setlist hardly changed throughout the tour), U2 were still kind of frightened to approach them again.