Through my work I hear many people complain about their boss not understanding what motivates them, despite the best intentions of their boss.
Typically, it seems as if there is a mis-match in how the leader acts, and how the follower wants the leader to act.
This article gives a simple explanation for why this is so.
If you're really interested in learning about how to take a more scientific approach to understanding what drives our behaviour, have a look at the Hogan Values Report. It's good.
Team Leader uses this report extensively, and has found it to be a highly effective tool in helping people understand what motivates them and others.