PARIS: I can’t eat dairy.
LORELAI: Okay, one [pizza] with cheese, one without. Cokes?
Paris later becomes quite an admirer of Lorelai, and I think this might have been the very beginning of it: her breezy acceptance of Paris’ dietary needs, and immediate problem solving. Lorelai works in the hospitality industry and is used to difficult customers, so she can easily handle Paris. That in itself is probably a refreshing change for Paris, and gets their relationship off to a good start.