I expected the front-line ICs to be united against middle-manager politics, but I found the opposite. Middle management was generally professional and transparent, while the toxic politics came from younger ICs looking to claw their way up the ladder.
I think it's a side effect of selectively hiring people who have been high achievers all of their lives. Drop them into a company where their intelligence is just average and many people resort to politics to get a leg up. Not everyone was like this, of course, but I've never worked with so many people rushing to throw their coworkers under the bus if they thought it might help get them closer to their next promotion.
There are people out there who simply optimize for getting as far as possible doing as little work as possible. These people are attracted to "winners". They'll do anything it takes to succeed, and anything it takes to avoid failure. It's the fear of failure that makes them especially unpleasant.
The world of work is far different and doing X,Y,Z is no guarantee of "getting an A" and some folks struggle with that for a while.
We often would have conversations about "picking your battles" and how just pointing out about how something is "wrong" is not the way to go about changing it.
(I learned this way too late, myself.)
It has also given me a new appreciation of why startups can be so efficient. The joke that every gmail redesign made the product worse but had to be done because someone needed to get promoted is no joke. When politics falls away and everyone's incentive is to become profitable or to build a good product the result can be magical.
The more people there are operating under any particular banner, the thicker the politics.
Probably most surprising was that there were a substantial number of people that (though very sharp) had pretty severe personality problems. The challenges and politics of dealing with these people seemed to dominate the merely technical challenges.
As a corollary, though their hiring filters were quite tight, these shops seemed to be only somewhat more productive than what you might see in a random US corporation. I would have thought it would be a day and night difference, but it wasn't.
A third minor surprise: Sometimes these companies spend huge on salaries but don't provide very good working conditions (office, desk size, quiet, decent bathrooms, etc.).
This has been my experience with engineers from Ivy League or similar schools. Really smart in a bubble, but with tons of weird neuroses that keep them from being fully-productive members of any team. That, and they never tend to stick around very long. It only takes a few bumps before I-could-do-better syndrome kicks in and they bounce.
Imagine you are designing the McDonald's hamburger wrapper. "Oh, your work will be shown to millions of people!" And nobody really cares. I'd rather design something smaller that is truly appreciated.