As in most jobs, moving up in a company is almost always politics and sociability. If you can act the way managers want then you have a chance. Working hard and doing a "good" job are secondary to making sure your higher ups like you and will want to help you move up. Out of the many managers in Costco I have worked for, 90% couldnt care less about you, 9% will help but wont go out of there way and then there is the 1% that is a good person and wants to help you improve in life. I have noticed Costco managers can be very heartless and selfish because this is the system that they run by. At the end of the day, managers are there to make numbers look good not to actually be a good leader. Working around corporate BS, making your boss look good and building a good relationship is key.