What's the definition of disappointment?
Running into a wall with a boner, but it only hits your nose.
Listen up, buttercup. So, the joke is that this dummy gets all excited, right? But instead of, you know, the good stuff happening, he slams his nose into a wall. That's disappointing because his boner didn't do its job. It's like when you think you're gonna get a participation trophy but then you don't. Major letdown!