I'm thinking of a few specific aspects of how the ACA passage happened.
The first is Pelosi actually convincing members of Congress to vote on the bill before reading it. I.e., her infamous "you'll have to pass the bill to find out what's in it" gambit. (It takes a lot of self control to not go into a tirade every time I think of that.)
The second is this: NPR did a great story talking about a variety of healthcare systems around the world, in terms of cost, outcomes, and implementation details. (Germany's looked especially good.) But nothing in the ACA seemed to indicate any of those vetted designs was seriously considered. It's like the authors of the ACA suffered from Not Invented Here syndrome. Or perhaps just as likely, the lobbyists didn't find it to their liking.