(Mildly risqué.)
An elderly couple, Margaret and Charles, are holidaying in California. Charles always wanted a pair of authentic cowboy boots. Seeing some on sale one day, he buys them, and wears them home.
He struts proudly into the house and says to his wife: "Notice anything different about me?"
Margaret looks him over, and shrugs. "Nope."
Frustrated, Charles storms off into the bathroom, undresses, and walks back into the room completely naked except for the boots. "Notice anything different NOW?"
Margaret looks up and says: "Charles, what's different? It's hanging down today, it was hanging down yesterday, it'll be hanging down again tomorrow."
"And do you know WHY it's hanging down, Margaret?"
"Nope."
"IT'S HANGING DOWN BECAUSE IT'S LOOKING AT MY NEW BOOTS!"
Margaret sighs and says, "Shoulda bought a hat, Charles. Shoulda bought a hat."