They 'know they are imperfect' if you bring it up, but they act like they are perfect. That is why it's better to move metrics than do anything actually beneficial, everyone is justifying their high performance review. If you hit your metrics your manager looks good, that means their manager is hitting their metrics, and so on. The people that suffer are the shareholders and users, but management is always optimizing to transfer as much wealth as possible from shareholders to themselves and you ride the coattails of that if you just chase metrics.