Eat that shit
When someone acts like they're totally in love with something that's completely stupid, and then do something even more ridiculous because of it. It's like they're so brainwashed, they're eating their own poop.
My boss said the new software was the best thing ever. I said, 'You're eating that shit.'
My girlfriend thinks that new shirt is the best thing ever. I said, 'You're eating that shit.'
My cousin joined a pyramid scheme. I said, 'You're eating that shit.'