Everyone wants something. They can call it what they will: desire, want, wish, longing, craving, yearning, or what-the-fuck-ever. It's all the same; everyone wants something and will do everything possible to make you perceive it as a need, a need only you can fulfill, a need you personally must fulfill.
We spend so much time trying to satisfy these desires when they are simply that — desires. We see them as needs because the requester displays them as such. We feel obligated to address them because they are handed to us as needs rather than desires.
Because we feel that someone needs something or that we need to fulfill the desire of someone else because they are important to us, we likewise feel obligated to act accordingly despite any other obligations to the contrary, including obligations to ourselves. We minimize our personal needs and desires in response to that which someone else needs. This is most notable within familiar relationships— friends, family, significant others, et al.
Many people, me included, allow arbitrary requests to dictate our lives even when we resent them. We sullenly accept whatever responsibility is thus heaped upon us while simultaneously disregarding our sense of self-preservation which is telling us we should do this, we want to do that, or we ought not do what is being asked for any number of reasons (too tired, it's illegal, it will hurt someone, it's contrary to our own moral imperatives, or any number of possible reasons).
Yet here we are, begrudgingly acting on the wants of others while ignoring our own needs.
I am not advocating selfishness. What I am referring to is the tendency of people — not all people, but those who care for others, especially those in their lives for whom they care — to respond to every request, no matter how whimsical or seemingly out of touch with your own life or self-centered it may seem.
This, I'm afraid, is the sacrifice we make for those we care about. This is the obligation of family and friendship. For people like me, this is also the obligation of life.
This obligation, however, does not prohibit lamentation or umbrage.