I was thinking he was missing his 'sun' which was what he had with Lori, and really missing his life when it was good, and all these normal things are making it hit him hard, what he has lost. And Jessie is very attractive because she represents the before, when life was good. The last scene with the overhead shot of Rick on one side of the fence and a walker on the other brought home just how close the 2 worlds are, and he was acknowledging that.

 

I agree with this but wanted to add that he looked at the A on his hand which again reminded him of the big threat of humans and you are never going to be fully safe.

 

Maybe Ricks looking at the A as Aaron, the dude that lied about 10' concrete walls.

 

I've enjoyed reading the different interpretations of the last scene.
Well done to the OP for putting this thread up and a big well done to TWD for making us think:zombies_cuinlove:

 

I agree with a combination of several responses. I definitely think he questions just how safe Alexandria and the physical walls are, and whether or not he can really trust the situation/people. I really also think he misses that outside world. Even though it's dangerous, unsafe for the kids, and unpredictable, he's transformed, and he knows that about himself, and he knows how to deal with the outside world, and doesn't need to work to change back or try to trust it.

That may make zero sense. I don't know, he could have just thought the steel felt cool to the touch, and wanted to stroke it for a while..

 

Just watched this one again...think the song choice at the end is brilliant...It's so appropriate - the tune is bouncy and upbeat but the lyrics are full of despair and regret and more than a hint of confusion.
The echoing out is great!