A dentist noticed that his next patient, a little old woman, was nervous, so he decided to tell her a little joke as he put on his gloves.
'Do you know how they make these gloves?' he asked.
'No, I don't,' she replied.
'Well,' he spoofed, 'there's a building in Canada with a big tank of latex, and workers of all hand sizes walk up to the tank, dip in their hands, let them dry, then peel off the gloves and throw them into boxes of the right size.'
She didn't crack a smile.
'Oh, well.. I tried,' he thought.
But five minutes later, during a delicate portion of the procedure, she burst out laughing.
'What's so funny?' he asked.
'I was just envisioning how condoms are made!'
(Gotta watch those little old women! Their minds are always working!)