The B.H. episode "Granny Learns to Drive" where Mel Blanc played the part of a hapless taxi driver was recently shown. I don't remember seeing this one before, it was one of the early black & white episodes. In it, Mel tries to collect his fare after dropping Granny off at home. Granny thinks he wants to take her to the fair when he asks her to pay the cabfare. He spends the episode trying to collect and by the end he thinks he's at an insane assylum.
It reminded me of when he played the telegraph messenger on one of the J.B. episodes. In it he telephoned his wife, after delivering the telegram to Jack, and gave the biggest sob story you ever heard to try to get a bigger tip and Jack double his tip to a dime.