a big joke
A big joke is when someone says they’re going to be rich, but they’re still broke and eating cereal for dinner.
My neighbor said he was going to buy a mansion. Now he’s living in a tent behind the gas station.
My friend told me he was going to be a movie star. Now he’s acting in a YouTube video with 3 views.
My cousin promised he would never fail a test. Now he’s crying over a math problem.