RORY: Please, don’t be mad.
DEAN: Why? Because I say I love you and you wanna think about it? I mean, go home and discuss it with your mother? Make one of your pro/con lists?
Dean’s angry comment suggests that there’s some real jealousy of Rory’s closeness with her mother at work, and perhaps the knowledge that everything in their relationship will be talked over with Lorelai rankles. He may feel that things would have progressed faster with Rory if her mother wasn’t always around.
This is the first explicit mention of Rory’s pro-con lists, which are apparently essential to her decision-making process. They will continue to feature in Gilmore Girls.