Select a point of criticism.
The illustration of Maslow's hierarchy of needs as a pyramid was not introduced by himself. Instead it's a interpretation of his model by others.
The image falsely suggests a strict order of needs, where one level has to be satisfied 100% for higher level needs to appear, which was not even intended by Maslow.
But where is the line to be drawn? Maslow fails to give an answer to that.
Maslow was not very scientific in his investigations.
He has not done any empirical research on the hierarchy of needs. So it is just something he came up with, and everybody is free to criticize its substance.
"This kind of research is in principle so difficult that if we were to wait for conventionally reliable data, we should have to wait forever."
Maslow's model fails to accommodate the role of culture and dismisses cultural relativity in its whole.
The hierarchy is heavily influenced by the individualistic western society and mirrors its self-centered values.
Furthermore, it is questionable if universality is given within a culture.
Maslow argues that a chronically hungry person's behavior is entirely motivated towards the goal of obtaining food.
However humans are very well able to prioritize the higher over the basic needs.
Some historical figures display this impressivly. Think of Mahatma Gandhi, Wolfgang Amadeus Mozart or the Greek philosopher Diogenes.
In their extensive review of research based on Maslow's theory, Wahba and Bridwell found little evidence for the ranking of needs that Maslow described or for the existence of a definite hierarchy at all.
Wahba, M. A.; Bridwell, L. G. (1976). "Maslow reconsidered: A review of research on the need hierarchy theory". Organizational Behavior and Human Performance.