It seems to me that humans need certain things, not only to survive, but also to function properly. To lack any of these things is to suffer. The question, then, is what constitutes a basic human need. This article is my attempt to answer that question. In doing so, I draw heavily on three sources; Maslow's Hierarchy of Needs, Victor Frankl's book Man's Search for Meaning and Wikipedia's article on self-determination theory.
In order to survive, humans need air, water, food and homeostasis. This category is pretty obvious, and I think everyone agrees on this one. (If you don't agree, try doing without one of these things for a few weeks and let me know how it goes for you.) Let's move on to psychological needs; those things without which humans either suffer, develop psychological problems (depression, social anxiety, etc.) or do both.
Humans have evolved two basic survival strategies; form societies and use tools. Thousands of years of social existence have bred into us a need to associate with other humans. This is a major source of teen angst. When a child's need for relatedness is not met, this can be a form of child abuse.
I believe that justified self-esteem is not a human need in itself, but rather a judgement of one's own level of competence (i.e. one's ability to handle life). This is why I use self-determination theory's term "competence" rather than "self-esteem". Note that it is not enough to be competent; one must also know that one is competent.
One place this idea becomes relevant is in technical support. Some callers hate calling for tech support because it forces them to confront their own lack of competence in using computers.
I believe that humans have an innate need to control their own lives. They need to be capable of surviving, but also of making important choices about how they survive. I believe that explains why creativity and freedom of speech are so important to people (i.e. they allow us to take an active hand in our own lives).
Interestingly, this need is central to the arguments of the The Unabomber's Manifesto.
Need for Meaning
As Victor Frankl learned through personal experience, happiness (and, in the extreme case, human survival) depends on finding meaning in our lives. According to Victor, humans find meaning in life by loving others, through accomplishment or in the endurance of unavoidable suffering. What separates this need from relatedness and competence needs is the need to recognize meaning in those areas. I attribute the lack of satisfaction of this need to humans' tendency to over-think things, which I think results in misguided cultural teachings.
This need is the central topic of Existentialism. If anything can be added to Victor's idea of meaning, perhaps it is aesthetics.
Security is the reasonable assurance that one's other basic needs will continue to be satisfied, and this is a basic human need. This category is interesting in that the difference between it and the other needs is not one of form, but of time. Note that while even reasonable assurances can be incorrect, the reality has a way of correcting our misconceptions (sometimes quite rudely).
Socrates once argued that when someone desires to keep what they have, then they desire something they don't already have (i.e. the future). I think the proper response to that argument would have been to say that while that is true, what people really want is to be sure that they will continue to have what they currently have.