It's amazing sometimes how tippy the top of a triangle can be.Ask Maslow.
Maslow's hierarchy of needs is often depicted as a pyramid consisting of five levels: the four lower levels are grouped together as deficiency needs associated with physiological needs, while the top level is termed growth needs associated with psychological needs. Deficiency needs must be met first. Once these are met, seeking to satisfy growth needs drives personal growth. The higher needs in this hierarchy only come into focus when the lower needs in the pyramid are satisfied. Once an individual has moved upwards to the next level, needs in the lower level will no longer be prioritized.
However, if a lower set of needs is no longer being met, the individual will temporarily re-prioritize those needs by focusing attention on the unfulfilled needs. The individual never regresses from one level to a lower one, however. An example of this fact may be a businessman at the esteem level who is diagnosed with cancer. He will spend a great deal of time concentrating on his health (Physiological needs) but would still value his work performance (esteem needs) and is likely to return to work during periods of remission.