Having recently been involved with a team that was being exhorted to "step up" and "go the extra mile" I noticed a range of responses from "lets go" to "why bother" to "I don't think so". After thinking about the response I identified several personal factors:
1) Internal motivation: some people are just go getters, you love to have them on your team, but sometimes they are seen as little puppies by other members of the team because they are perceived as being overly eager to please. Motivating this type of person is trivial.
2) Internal ambivalence: some people just don't have that drive. "Programming as a job" is an attitude that some in our industry have. These people do a good job while they are at work, but when they are not at work - they aren't. Motivating this type of person is more difficult since your have to convince them that the extra hours are worth it to them. The typical example for internal ambivalence is the programmer who don't read technical material, go to conferences or training. They expect to pick up everything they need to know between 9 and 5.
3) External personal distraction: there are those who may have the internal drive, but because of various personal/external reasons choose to place other priorities in front of work. Motivating this person is not likely to succeed without significant effort because they have consciously prioritized their work life at a lower level. An example here is the developer who's wife just had twins and is bed ridden. Attempting to get this person to spend more time at work boarders on malfeasance.
There are also a couple of factors the motivator brings to the table:
1) Trustworthiness: in several jobs I have seen otherwise motivated individuals who don't respond to motivators because the individual has determined that the motivator is not trustworthy. Thus any promise in the world will not help because the individual doesn't believe the messenger.
2) Disagreement: Closely related to trustworthiness is when the individual doesn't agree with the path the motivator is proposing. This one is trickier since this could just be resistance to change.
3) Approach: here the individual is not being motivated correctly, the carrot is offensive, or the individual is just not interested in that particular carrot. Typically money is used as a motivator, but money is not equally important to everyone. A great example here is the "employee of the month" award - I bet you can't find developers who are motivated by this kind of reward.
Which kinds of motivating factors have you seen work for or against the desired outcome?