Well, chiropodists like jokes. But opticians like them.
Because he didn't C#
They both work on crowded platforms.
Because 7, 10, 11!
Did you ever notice he seems to start off all of his jokes in one of two ways
Because they both "practice" their professions.
Barbers.
Prism (Note: I made this joke up. Sorry if this little note refracts from the humour.)
Because it's inefficient!