what motivates one to work

After hitting some "fair" monetary point, 3 things motivate people at work:
1) a sense autonomy and self direction
2) a sense of mastery ie getting better and better at something that matters
3) a sense of purpose ie what your doing matters to more than just myself
For enduring motivation, these 3 criteria supersede the carrot and stick method empirically. However, it is emphasized that the compensation should be at a level that the money doesn't really matter. This is backed by 50 plus years of behaviorial science. If people focus mostly on the reward, the job deteriorates. High stake short term incentives leads to bad work... Daniel Pink author of Drive
To employees, Pink offers advice on how "type X"es — his coinage for people who prefer external rewards — can enroll themselves in the burgeoning ranks of the "type I"s, driven mostly by inner rewards. The difference matters: Type I's have better long-term performance and well-being, he argues.
http://www.danpink.com/