I think jealousy has been a key factor for deterioration of one's splendid performance with time at work. Colleagues generally gets irritated of the executive with more skills and honesty. Diligent employees may be given more work and more pay for it. Sometime his/her colleagues may have the fear of being fired out of their own job because of an intelligent person handling more responsibilities in an intact manner. Consequently they may wage consiperacies against the intelligent one to drop his/her rank and sustain their own positions. Such kind of situations severally damage chances of the efficient executive.