and they keep bringing Lori back (unfortunately)
They only kept bringing Lori back because they'd signed Sarah Wayne Callies for an entire season and killed her character off after her third appearance. Might as well recoup some of that expenses when you still have her. I'd be very surprised if we see her in season 4.
I actually thought a lot of it looked like stock footage. Anyway, one of the final scenes of the season finale seemed to make it clear that Rick has gotten past that, when he looked up and was no longer haunted by her ghost.
Of course, Sarah Wayne has form in the whole 'bring a character back from the dead because of fan outcry' thing - remember how her Prison Break character was killed and, lo and behold, that wasn't actually her head we saw in a box?!