I think that the only reason why anyone does anything is because they want to feel certain feelings or feel certain ways about themselves. Sometimes more accurately, they want to avoid feeling certain feelings and avoid feeling certain ways about themselves. The combination of those feelings or lack of certain feelings would contribute to their fulfillment, which is what people ultimately want.
However, fulfillment could come from many different things or different combinations of things depending on the individual: family, love, career, wealth, freedom, hobby, competition, progression, fame, attention, peace, excitement, etc. Each person has to develop an intimate and nuanced understanding of themselves and what exactly it is that they want.
Thinking about life in this manner and acquiring that self-understanding, it becomes much easier for people to start living intentionally and ultimately get what makes them feel fulfilled.