The Barber and the Mother-in-Law

A man gets a haircut, and the barber keeps asking, “So… how’s your mother-in-law these days?”

The man replies, “She’s fine.”

A few minutes later, the barber asks again, “And your mother-in-law? How’s she doing?”

The man starts getting irritated.

“I just told you she’s fine! Why do you keep asking about her?”

The barber grins and says, “Oh, it’s not because I care. Every time I mention your mother-in-law, your hair stands straight up, and that makes it much easier for me to cut.”