Needs motivate us toward a limited range of goals, the specifics of the goals we pursue within that range being decided by personality. For example, my need for competence motivates me to finish all my tasks at work but also demotivates me from any goal that involves repeating the same task for a specified period. The same goes for my needs for achievement and autonomy, which combine to motivate me to choose a field that involves contributing to a team effort on my terms with discrete tasks. I prefer being a salesperson because of my personality. I could just as easily satisfy those needs as a baker, but I would never enjoy being a bank teller