Dipped a toe in

Image description: A naked woman with short brown hair stands along the shore of a beach, with one of her legs in the air, water dripping from her toe. She looks at the camera, smiling.

Caption: "God, you're so gullible," Brad said in a new voice. "See, I dipped my toe in, and nothing happened."

Commentary: Generally, I prefer shorter captions to longer ones. Mine aren't all this short, but I generally think the picture should tell most of the story, and the caption should be readable without zooming in on the picture. There are a lot of excellent longer-form captions, but at some point you're just writing an illustrated short story, and that's not a job for Photoshop :).