Well, I dunno about him, but with dogs... I only pet dogs that show an interest in me after sniffing my hand- anything else would be rude. The ones that get scritched almost inevitably wind up pushing their heads up against my leg like a cat, which is a little unnerving when it's a full grown pit bull someone bought for home security purposes. The others jump up and try to lick my face or something like that.

At least I recognise the urge as the same one I had re: Agent Mulder when he wasn't being a jerk.