So... what is it? He was never portrayed as being clueless or inconsiderate or sloppy or a jerk to his neighbors before (except for Dwight, who earned it by interfering with his biggest client way back in season 1).
I think part of it is that they overestimate how likable he is. There's a lot of writers who seem to want to "take Jim down a peg" and show him losing or being flawed or having people get mad at him as if this is the first time anyone has thought badly of him, when really he's not some character people think is perfect to begin with. They don't seem to like to do that for Pam. She's flawed and makes mistakes, but she isn't hung out to dry like Jim in this ep. Pam gets portrayed far more as the good-hearted victim.
I think with the business it's supposed to be more that Jim went through an understandable and ultimately good crisis about his life, but was at first afraid of telling his wife. So he kept it secret--but not to the point that he was really committing anything on her behalf. When Darryl tells Jim it's not real if his wife doesn't know, he's right. All Jim had really done at that point was get himself into the discussion. Pam could have said no--he just made it harder by having already told the guys yes. So he was wrong, but it's not like suddenly Pam's bank account was invested in Athlead or anything.
Once he did get onboard I'm not sure he's really supposed to be as selfish as he comes across. I mean...it's hard to pinpoint it. Clearly he's often having fun at work, having his best day ever, enjoying the bachelor pad. But I don't think it's that he's supposed to be selfish so much as this situation is enjoyable in some ways for him and he's so taken with it he's distracted by it.
It was possibly just dumb to come up with a sudden "he's a big slob" thing for Jim because they made it seem like such a metaphor for the situation they pretty much came down on Pam's side: Jim's using Pam's cup by disrupting her life for his own use. Jim's acting like he's the only person who matters in his marriage just like he treats his obviously shared DVR as if he lives alone. (And really, who does that? It's not like Jim had any reason to not want Darryl to have his shows. It was supposed to be completely ceaselessness that made no sense.) But at the same time I can't believe they really see Jim as being selfish by not agreeing with his wife that the best thing for them and their family is obviously to keep their joke jobs at the dying paper company. If they'd played the story a different way maybe Pam would seem more like Jim in wanting him to give it up. (He has in the past supported he similar desires, especially with Michael Scott Paper--different situation but same automatic support of something she thinks she needs/wants for herself.)
Edited by Sister Magpie, Feb 3, 2013 @ 3:53 PM.