I have to first say that I totally understand why these guys are trying to be tour guides, but in this case it was depressing!
A guy who was actually pretty sweet approached my friend and I to see if we wanted a guide. He made the hardest sell, first saying he spoke 20 languages, including English IN 4 DIFFERENT ACCENTS! Then, he said he could whisper quietly (like this) in one corner and we'd hear it over there, and on and on. He truely seemed hurt that we didn't want a guide. Actually, we just wanted to look around a bit.