Which of the humanistic theories (for example, Rollo May, Rogers, Maslow, existential) do you feel or believe is the most useful for understanding personality including human nature?

Which of the humanistic theories (for example, Rollo May, Rogers, Maslow, existential) do you feel or believe is the most useful for understanding personality including human nature?

select one of the humanistic theories and read at least two outside sources as references.
Which of the humanistic theories (for example, Rollo May, Rogers, Maslow, existential) do you feel or believe is the most useful for understanding personality including human nature?
What research can you find that supports your belief or feeling?  How much do the humanistic theories appear related to positive psychology?
Explain what makes the theory you selected more convincing than alternative theories.
What challenges might you find in order to research this theory and test related hypotheses?