MnCastleFan said:

You would have thought that Castle would try to give her a hug unless he plans on seeing her in the future. Come on, that would be the perfect time to get a 'free' hug with little consequences since he was leaving. If you notice how affectionate he is towards his daughter who he loves, a hand-shake just seems wrong for a guy like him.

Maybe they could have started the hug and both get a phone call, so they quickly stop. Then they find ou the news about working together and get a little more serious.

The ending was classic with Beckett happy to ask if Castle was coming with her to the next case and Castle running like a happy puppy.

It would've been nice to have had a higher level contact than a handshake but I can kind of understand. I'm a huggy type of person by nature but there are people whom I am not comfortable giving a spontaneous or purposeful hug either because I know they would feel uncomfortable with it (which could be a little bit of Beckett's feelings) or I like them too much and giving that hug would be filled with so much unknown ramifications that it is better to go without.

At the same time, it would have been perfect in my imaginings if Beckett and Castle had at least parted with one of those soulful kisses that is filled with regret at unexplored feelings…right before they receive their respective phone calls. I'm just a hopeless romantic and any contact between Beckett and Castle sends me happily to the moon. :) The repartee between Beckett and Castle is great though, but a little bit more physical contact (like a hand on the elbow or shoulder? Please?!) would be enough to tide me over.

I would dislike seeing them get together so far down the road (like season 4, as per Stana's interview reply) that I get sick and tired of the unfulfilled sexual tension. A relationship is wrought with emotions and complications and it would be nice to see these two characters explore and play with those. Something new and fun. I'd be happy.