The worst sales pitch I ever had was when the salesmen (only 1, thankfully) was about 5 minutes into his spiel when I had to interrupt him to ask a question. He answered the question, but when I asked him to continue, there was a momentary pause, and then he started from the beginning, VERBATIM.
I let him get about 8 minutes into the spiel, and then asked another question. Again, correct response to the question, but when I asked him to continue, the same slight pause, and he started over again from the beginning, again verbatim of what was said before.
I stopped him, ended the meeting, and told him to call me when he knew his material better. He never called.