How do you answer 'What matters to you the most and why'?

This is a question about your values. Don't feel that you need to lie and say work is most important to you. If it is not -- and generally it is not -- be honest.

Any job searcher needs to do serious introspection. Carefully consider what is important to you and why. Try writing it out. Ask yourself questions and write out the answers as if you were aggressively interviewing yourself.

Values are not a simple hierarchy. Everyone has multiple values that need to be balanced. One of them should be pride and satisfaction from your work. That should be mentioned with the others in a job interview.