Because you don't have much hope. You need more happiness in your life.
Because you have no optimism, you do not look at the bright side of things. You don't jump at opportunities to expand your life and experiences, you don't have any interests or hobbies which could carry your life further. Try harder in life, then it won't feel that way.
your young,have a long future ahead.make changes.
You must have went down the wrong road...