Maslow was a theorist who among others came up with a list of needs. He constructed these needs in a hierarchy or pyramid which shows the needs ranked based on which ones are needed more than others. The most needed needs are at the bottom with the needs being less and less needed as you go up the pyramid or hierarchy.
The most needed need is physiological which would include food, shelter and water. These are things that people need to keep their body alive. The next need is safety. It is needed very much but not as much as the physiological needs.
The next need which is in the middle of the pyramid is love and belonging. Then the next need is esteem. The last and least pressing is self-actualization needs.
The least pressing on the hierarchy of needs put forth by Maslow is the self-actualization needs. This level is basically the level where passions and wants can easily be fulfilled. Since it is the last of the hierarchy levels, it is the least important. The idea is that following your passions, realizing your full potential, can be done after you have figured out the rest of the issues the hierarchy covers.
For those not in the know, the hierarchy, from lowest to highest, is as follows: physiological, safety, love/belonging, esteem, and self-actualization. At the lowest is the most basic of human needs, such as food, sleep, shelter, etc. Safety would be where abuse situations would fall. Love and belonging is making sure you have a family. Esteem is making sure you love yourself.