Bureaucracy and politics

Oh, the bureaucracy and politics. Woe be upon you if you work on a project or in a group that senior management doesn't find sexy. And there was always poor direction from senior management who couldn't decide what they wanted, since their decisions were based purely on their speculative opinions.

Despite intense recruiting, more people left faster than replacements could be hired.The hiring bar was correctly held high, but there were also far too many ways to fail an interview for arbitrary reasons. Amazon simply can't turn down good people and meet its hiring needs 

Also, for most teams with excessive on-call, being woken up in the middle of the night gets very old after a while. Amazon pretty much destroyed a few of my colleagues through excessively hellish work schedules for no apparent reason since the other dependent teams weren't on the same timeline, so it was always hurry up and wait. This is not the best way to make your hard working employees feel valued.