Expanding on an idea

Pyramid of Needs
Maslow's hierarchy of needs is often depicted as a pyramid consisting of five levels: the four lower levels are grouped together as deficit needs, the top level is referred to as being needs. While deficit needs can be met, being needs are a continuing driving force. The basic idea of this hierarchy is, that higher needs come into focus only after all needs lower in the pyramid are met. Growth forces result in upward movement on the hierarchy, whereas regressive forces push prepotent needs down in the hierarchy.

Deficit Needs
Physiological Needs: If all of a human's needs are unmet then the physiological need takes the highest priority. Given hunger for love and food, a human is more likely to find a solution for the latter first. As a result all other desires and capacities are pushed on to the back burner.
Safety Needs: When the physiological needs are met then the human turns towards safety needs. Safety attains the highest priority over all other desires. However, in the case of acute danger, safety comes before physiological needs (for example eating).
Love Needs (Belonging Needs): If safety and physiological needs are met then the human being gravitates towards achieving fulfilment of love needs. A note worth making here is that sex is not equivalent to love. Love can and is often expressed sexually. Sexuality can at points be considered solely for its physiological basis.
Esteem Needs: This refers to the valuation given to oneself by other people.

Being Needs
Self-actualization is the instinctoid need of a human to make the most of their unique abilities. Maslow described it as:

A musician must make music, the artist must paint, a poet must write, if he is to be ultimately at peace with himself. What a man can be, he must be. This need we may call self-actualisation. (Motivation and Personality, 1954)

While other needs can be met fully, self-actualization is seen as 'growing', i.e. as a continuing driving force. This is related to tikkun olam in the Jewish tradition — using one's skills to fix what is broken in the world.

Critique
While Maslow's theory was seen as an improvement on previous theories of personality and motivation, concepts such as self-actualization are somewhat vague. In recent years, the theory as a whole and especially this term have been somewhat overused and are sometimes perceived as psycho-babble.

It is also problematic to operationalize and test Maslow's theory. There is no proof that every person has the ability to become self-actualized.

from Wikipedia