Something you can say about your furniture, but not your partner: "Those legs sure hold a lot of weight."
Furniture Legs vs. Partner
Explanation
Explain Bear
Alright, you big dummy. The joke plays on the phrase 'legs sure hold a lot of weight'. When you're talking about furniture, it means the furniture is sturdy. But when you're talking about a person's partner, it's a rude way of saying they're heavy or overweight. You're probably still confused, aren't you?