You never know what you will end up doing by the end of the quarter and sometimes by the beginning of it either. The head of engineering is like a charade position, it will change every six months and all of them will come in with a different view and agenda, so don't plan ahead!. Sometimes on all-hands meetings, you get really scared about the company vision and economic facts, because they are saying one stuff and the next day doing something completely different, for example: firing half of the company when they were no clear signs of financial problems on any previous meeting. They keep grabbing new ideas and presenting them to the engineering team as the new panacea, and at the end of the quarter they realize that is not that such and hours and a bunch of code never gets live or worse, it's a useless feature for the clients. Sometimes you get the idea the actual customers are misled to believe in a product that only exists on paper and pay a small fortune for a useless tool.
Management: What can I say, there are great people there and not that great also but everything in life behaves the same way.
PO: Sometimes you feel that you are implementing features to suffice some tantrum of the product owners instead of adding some real usability to the final product, is easy to realize that when you get to know the percentage of usability of all the features you've done so far.
UX: that's something to write home about sometimes as an engineer you got completely lost on trying to do simple stuff on the platform like viewing details just to say an example. It really amazes me how the final user learning curve must be.