I can't explain why, but for me, House is like Law and Order (the original): I'll gladly sit and watch an episode if it's on and I've got time to kill, but I have no real drive to watch every episode, or explicitly fill in ones that I've missed, or record new seasons.
And it's not because I don't like the show, or the characters. In fact, the opposite is true: I love House, I love Wilson, I love McCoy, and Briscoe, and the new EADA that replaced McCoy when he got bumped to DA. And I'm fond of several of the supporting characters, too... but there's very little growth, or dynamism, or development of characters. It's not completely stagnant, but that's only apparent when you don't miss episodes and view in order; but the pace of those developments is so glacial that it doesn't drive me to watch to see what happens with them. It remains, to me, an episodic show on the most fundamental level, where I can sit down and watch two episodes from seasons apart and rely on my understanding of the characters to be pretty firmly on track. And then, unlike a sitcom (which are similar in their level of staticity), individual episodes don't cause them to be must-watch things for me. They're entirely adequate to entertain me, but they're very routine. Sitcoms make me laugh (or at least, the ones that I self-select by continuing to watch them), whereas episodic drama simply entertains. There's nothing wrong with entertaining, but it's not, in itself, compelling. I have a lot of potential sources of entertainment in my life.
When I'm sick and curled up half-asleep on the couch, though, and there's a marathon (or TNT in the case of Law and Order) as a reliable source for repeats, though, the last frame of this says it best...