It is a very deep and philosophical question. I think the main thing in life is  love in its wide meaning. It is love to your family and friends, love to yourself, love to your job and so on. I think it is very important to be in love with life. Sometimes life can be difficult, but if you love yourself, you can make your life and life of others much better. If you possess such feeling, then you will be kinder and more respectful to other people. Unfortunately, this is what our society still lacks.