User blog comment:SaganamiFan/Aidan Gillen/@comment-4358023-20120511045709

I haven't read the books (please don't spoil if you have), but I figured he was being more reserved because things seem to be getting out of control at Kings Landing after the death of Ned, and Littlefinger had told Catelyn he was going to help them prior to that. Basically, he had a hand in screwing everything up and starting all of this total crap, causing Catelyn to be rightfully angery at him. And because he loves Catelyn and caused her to be upset, he isn't happy with how things are going, so he no longer has that...thing (for lack of a better word) that made him seem like such a joyfully manipulative bastard.