In my opinion seeking promotion has to be related to the self-esteem.
I think this because everyone's nurturing comes from his or hers inside. If you trust your own strengths and your own capacities you can reach any goal you can have.
If one does not have confidence in herself or himself she or he feels powerless and can not go on. In this instance she or he has to look for improvement otherwise can become a pray for drugs, alcohol or even diseases. When one's self-esteem is too low the tiredness and psychiatric diseases can find a good place to live. Most of the time the stress is the reason for which the level of self-esteem is getting low. To get yourself on your own feet you have to do something to improve your image in your own eyes.
On the other hand, if the self-esteem is high you can do everything you want even to compete with a stressful situation and a demanding job. Many times one is looking for a promotion only to get confidence in herself or himself and to be recognized as a leader by her or his co-workers and the society. But getting a promotion is not improving only your self-esteem, is raising also the money in your account, so your material status gets improved.
Personally I am seeking for a promotion only because I feel I can do more than I am doing now, I can assume much more challenges and I can prove myself that I am valuable enough to get respected by the members of the society which I live in. Briefly I feel I haven't reached my potential yet.