A lot of mediocrity among engineers: some of them barely knew how to program, others would spend more time on social media than working, or even some more interested in running their own interests before their assignments. If you end up locked up in one of these teams, it's very hard to get out.
Also lots of politics going on, way too much for me. I was also not a big fan of the widespread SAFE methodology and the over-reliance on tools like Rally which created lots of overhead.
Working with Japan is interesting but also very frustrating at times, especially as they have ownership of the platform.
Finally, very limited remote work options, given that most of the work requires devkits that can't be accessed outside the office.