You're a team player; nothing great has ever been accomplished with just one person. Anyone who says otherwise is probably a not very nice person, and not someone who you feel the need to be associated with. You make friends for life, and you take those relationships very seriously. Like, blood oath seriously.
There is nothing that has been invented that we cannot live without. Because, for something to be invented we've had to not have had it before. People sure would piss and moan though if the car was taken away....to answer your question.
In fact, according to SurvivalTopics.com, the longest a person can go without water is 10 days--without food, it's four to six weeks. However, due to certain other variables, these numbers can vary. Second to oxygen, water is the most important compound that the human body needs for survival.