Completely Ignored Me

I worked at Amazon for two and a half years and just left this past summer because I gave up on my managers ever caring about me. They completely ignored me from when I started until I left and never gave me any career help or anything else. They treated everyone the same whether they were doing good work or not and just gave everyone the same mediocre reviews. Instead of spending time managing the team, they seemed to be always working on a six pager to impress their directors and VPs and nothing else mattered apparently. Most of my team members felt the same way, which is why three quarters of my team quit over the past year. We tried telling our directors and other leaders about our situation, but they didn't seem to care either. I really don't know why Amazon seems to hire so many selfish managers because I'm sure they will eventually run the company into the ground.