Confession: I suck at guided tours. Having someone talk at me constantly while I'm trying to take in the sights is like having someone explain the plot of a book to me while I'm in the middle of reading it. It drives me crazy. We had a 3 hour tour of the Mesquita and I was so irritated by the end of it that I can barely tell you anything about it.
But Mum loves that kind of thing, so I just kept quiet and waited till we got ice-cream at the end.