I just had plastic surgery: They cut up all my credit cards. Except for my Discover card, which nobody takes.

Liebman’s joke hinges on a bait-and-switch: “plastic surgery” is expected to mean cosmetic surgery, but she literalizes “plastic” as credit cards. The punchline then pivots to a familiar consumer gripe—Discover being less widely accepted than Visa/Mastercard—so the “surgery” fails to solve her spending problem because the one card left intact is the one she can’t readily use. The humor also lightly satirizes self-improvement culture: instead of changing habits, the speaker seeks a quick, external fix, only to be undercut by everyday economic reality.