Imagine being at a dinner party, and someone asks you to bring a side dish. You whip up some mediocre pasta salad, and you're expecting a 50/50 chance of getting a free pass, right? Wrong. The host asks you, "So, did you make the most expensive side dish you've ever made?" You're like, "Uh, yeah, I spent like, $10 on fancy cheese and stuff." And then they're all, "Wow, that's so impressive! You're so generous!"
But let's get real, you're not that impressive. You just made a $10 pasta salad. That's not impressive, it's not impressive at all. But the host anchors you into feeling like you've done something special, so you start to believe it's true.