What's the difference about 'what you want' and 'what you need'?

What you need is crucial to staying alive. What you want is optional and not necessarily crucial to keep yourself alive. We all need food, sleep, and water to survive but we do not all need transportation to survive. Some things in this world seem like necessities when it only really just helps us by being convenient. Our needs are more important than our wants if our aim is to survive. However on a psychological level, to keep mentally healthy sometimes the things we do not need provide us with security in regards to mental health. Also, some people don't care about surviving or come from fortunate backgrounds so material possessions are placed on a higher importance than their needs in their minds.