I went on a blind date, and my date showed up with a seeing-eye dog.

This joke expertly mines humor from the double meaning of a common dating term. A "blind date" usually refers to meeting someone you haven't seen before, often arranged by a mutual friend, where the surprise is in their personality or appearance, not their literal vision. The setup immediately twists this idiom, making the "blind" aspect surprisingly literal with the arrival of a seeing-eye dog, subverting our expectations in a clever and unexpected way.

The punchline then takes this literal interpretation even further, playing on the practical function of the guide dog. The irony is that on a date with a visually impaired person, the dog, an animal, becomes the "seeing" partner, offering a comforting and amusing solution to the very human problem of getting home safely after a night out. It's a delightful bit of wordplay that hinges on the audience's understanding of both dating conventions and the vital role of service animals.