there are several reasons unhappy lot of dont know how to enjoy their life they always expect more than things what they have now that is the main reason for people are unhappy lot of people dreaming about what they havent. and also some bad feelings cause to the people unhappy
People are unhappy because they need something/someone they want to have in their life. Maybe a material or someone like friend or somehow like a relationship they want to have in their life, to enjoy life with someone else to the fullest. But before anything else, you MUST enjoy life for what you have right now before dreaming what could you have in future.