I always love to think that Castle wants to call Kate baby or something. Castle's like "Can I call you baby?" Beckett rolls her eyes and gives him a dead glare. "Babe? Sweetheart? Sugar?Doll? Beautiful?" more dead glare. "Honey will do...." Beckett says when she sees Castle is disappoint. She couldn't help but finally give him the right to call her that. When Castle hear that he cheer up immediately and want to use it right away. "...but not on the work" Beckett finish the sentence. "Scout's honor, honey!" Beckett grins. "Can I call you hon?" "Shut up, Castle"