On Gilmore Girls Luke and Lorelai started out as friends and took a slow burn toward romance. They never lost their ability to push each others buttons to keep things fresh and we still don't know if they ended up together forever.
Dean: You said 'boyfriend'. Rory: No! I just meant boyfriend in the sense that the whole defending me thing was very boyfriendy, but only in the broadest sense of the word, which doesn't even apply at all here.