JESS: And Dean would’ve eaten this? [holds up a container]
RORY: Yes, he would have.
[Jess tastes a forkful of the food and makes a face]
JESS: Dean is an idiot.
RORY: Dean never would’ve fallen for that.
Dean is often depicted as less intellectual or less quick-witted than Jess, so it’s satisfying to see Rory gleefully point out that Jess has made a naïve error that the savvier Dean wouldn’t have. It’s a reminder to Jess that Dean actually knows Rory, and that they have a shared history of which Jess is ignorant.