I saw an article at Facebook (I believe that is the most useful feature of Facebook) about the opinion of alibaba.com founder on the worker resignation. It's in Chinese, I will try to use my limited English with the help of Google to translate it to English.
员工的离职原因林林总总，只有两点最真实：1、钱，没给到位；2、心，委屈了。这些归根到底就一条：干的不爽。员工临走还费尽心思找靠谱的理由，就是为给你留面子，不想说穿你的管理有多烂、他对你已失望透顶。仔细想想，真是人性本善。 - 马云谈员工离职。In English:
There are various reasons why a worker left, but there are only two reasons are real: 1st, money, not up to the level; 2nd, heart, being wronged. All these are because of a roof cause: not happy in the work. When the worker leaves, he still tried to find an excuse so that he wouldn't drop your face, he doesn't want to disclose how bad is your management skill, and how disappointed is he on you. Think thoroughly, human originally is still kind.When I left my previous company after 10 years of servicing there, this article expressed my real reason why I left. Another article said, a worker doesn't leaves his company, but he leaves his management. A very simple fact, but how many management willing to accept that they are failure in management? How many willing to change? Worker is the most valuable properties of a company, without these workers, basically a company is a just an empty walking soul that has no direction and progress.