Thinking about this, it's not so easy to call a particular problem.
[*] Laziness. This is the person who said that doing chores counted as trials and tribulations, basically. Like okay, I have done very little physical work in my life, but I'm 99% sure I've done much more than Chris ever has. Being the tall girl, a lot of boy work would get put on me when they could hide somewhere and pretend they were busy. I've helped move couches and tables, small things in the grand scheme, but I get the sense that Chris has never had to do even that much. If Chris had to move a couch from outside to inside, no doubt he would have to pause a bunch of times to "rest" or whatever. So his parents never made him do anything at all physical and that reinforced his laziness.
[*] In 2013, this reinforced laziness isn't seen as laziness at all. He thinks, whether it's because of his autism or not, that he's too special to have to do any kind of work. He got SSI in lieu of work, he spent 6 years on a 2 year degree, he never had to work for anything, and he thinks it's because he's special. Instead of realizing like a normal person would that he isn't entitled to things without working for them, he assumes him being 'special' is all he has to have to get through life.
[*] Delusion. The view that he is special and thus doesn't have to do what the rest of us do is nothing more than delusion. He has spent so long deluding himself he's special and doesn't have to work that he wholeheartedly believes it, even in the face of life going the exact opposite. The delusion has been growing no doubt thanks to Borb's ridiculous views on trolling, Mike Snyder, Lucas and Mimms, etc. He thinks the entire world is out to get him, a real life kick the autist in perpetuity. He believes this because he is always right.
[*] He thinks he's always right. Autism may as well be analogous with Always Right Syndrome in OPL's mind. Because he's special and entitled to his laziness, because the delusion inspired by or helped along by his parents is so strong, Chris is under the impression that simply believing something makes it right. Magical thinking is one way of saying it, but it's more than that, because even people who are intense into magical thinking can realize they're wrong and regret it. Chris has no capacity to admit, in a TRUE and HONEST way that he's wrong, because he just doesn't believe it can happen. In his mind, he is special, he is entitled to do nothing but gain everything, and therefore, he is right about everything.
[*] He can't grow up. As many have pointed out time and time again, Chris is stunted developmentally. He is still living somewhere between early childhood and the mid-teens. Whether he has the capacity to mentally age as far as 20 remains to be seen, but as yet, he has totally and completely refused to let go of any ridiculous belief that should have been proven untrue over and over. He is the definition of manchild. He is a child in a man's body, likely by sheer force of will and terrible parenting.
That's just a few of the things that could tie as his biggest problem. It's not just one thing, it's an entire mindset, a Chris-set.