I didn't like this week's episode. I can't believe that Castle would be so gullible as to fall for all that psychic/medium crap. He's a mystery writer and an experienced amateur detective -- he should have no trouble seeing through the scams and understanding how frauds like this play their tricks. I mean, heck, they use the same observational methods Sherlock Holmes did, they just lie about it.
Also, someone who's as precise about grammar as Castle was shown to be last season wouldn't have made that crack about how hard it would be to "possessive pluralize" the name Cassias. It wouldn't be "The Cassiases's car," because a plural noun is made possessive with a simple apostrophe at the end, not an apostrophe-s: "The Cassiases' car." In fact, one or two characters other than Castle did correctly use that possessive plural later in the episode (although modifying a different noun).
I also didn't like the way Castle only seemed affected by his mother's tragedy in the scenes where he was with her. Beckett was even surprised to see Castle interviewing the reality-show guy when she expected him to be home dealing with the family crisis, and he seemed totally unfazed by it.
So basically, I guess most everything I disliked about this episode came down to its portrayal of Castle.