Oh boy. Where to start?
The company I worked for (lets call is Ace LTD - because it was an ace company to work at) understood how to treat their employees with kindness, grace, and respect. They created a fantastic envrionment full of hard-working teams who pulled together to get the job done. We shared fantastic bonuses, and benefits. They understood that you were primarily at work to pay the bills, but why not actually enjoy yourself whilst being at work?
Ace LTD was aquired by IRIS. That's where the trouble started. For the first year we were largely left alone. The only thing that changed was that a few senior staff left and were replaced by, frankly, idiots who didn't seem to either care or understand what we did. I learned later that they did - in fact - simply not care because this was not their first IRIS-Aquisition-Merry-Go-Round.
The other thing that changed was that we lost around 8 days of annual leave and our Christmas thank-you/bonus.
Now that most of the senior staff had left, IRIS came for the staff who worked in functions that could be centralised. They were discarded in what can only be described as a very dodgy (some might say illegal) redundancy process. Firstly telling the staff that they were being made redundant. Then - when the legalities around redundancy was explained to the senior HR people - back-tracked but denied that anyone had said the word "redundancy". There was lots of gas-lighting and weird metaphors used (including "mutual decoupling" to describe the redundancy process).
Lots of teams got new team leaders. Some even were blessed to receive a merry-go-round of new line managers every few months. Not once in this period did any line managers take any interest in Ace LTD and what they did. I didn't have any 1-to-1 time with my managers for 2 years. I'm not even sure they knew my name.
This horrific man-management is actually a pro: my managers (plural, I had so many different ones!) took so little interest in me and my colleagues that we just pleased ourselves. We finished and started work when we wanted. Took days off and nobody noticed. We noticed after a while that even being "available" on Teams didn't matter because nobody ever got in touch with any of us. We were stealing a living. It got to a point that I was so bored that I completed loads of free online courses and got a fabulous new job out of it.
We all learned very quickly what the deal with IRIS was: Buy profitable company. Add "by IRIS" to its name. Scalp the customer-base and try to cross-sell. Sack anyone whose labour could be gotten cheaper by centralising or moving to India. Ignore the customers who complain. Buy another company. Refinance for the private-equity goons. Rinse and repeat.