The Google search, "What is life all about" has gotten quite a few hits. The very top result is users.aristotle.net, which explains thus:
"You cannot be classified as useless, because you aren't really supposed to have to make yourself useful. Look at the natural world. What is the use of a tree? Well, it has many uses, but it isn't TRYING to be useful. There's the difference. It's just doing what it wants (or so we assume) and in the process of doing that it does its job in the natural order of things. Despite all the rantings of moralists, you are in the same boat. The only way you are ever going to do an ounce of good in the world is to do what you want. Do what makes you happy, or at least what distracts you from your misery.
How, you may ask, does doing what you like do any good? Look around you. Look at people who seem to be trying very hard to be useful. Are they really doing good things for people? Or do they make everyone around them miserable with all their moral uppidyness and incessant busy bodying? I suspect it is the latter. The people who really do others some good are the people who are doing what they like and who aren't very interested in being useful. They are usually interesting to be around, because they are doing things that interest them. They are often fun to be around, because they appreciate fun and know how to laugh and not take anything too seriously. They inspire other people to figure out what it is that they want to do by example, thus causing more people to be interested in life and interesting to be around, fun loving, etc.
Out of all the people we meet in life, these people who are doing their own thing are the people who have the most profoundly positive impact on us and thus make our lives richer in the most fundamental, meaningful way. Can you really call that useless? Sure, working in a soup kitchen will feed people, but if you're being a martyr about it because you don't really want to be there, everyone around you will see right through you and hate you for being moralistic and insincere, and you will end up doing more harm than good. So, revel in your perfect uselessness. It's the useful thing to do."
There are other explanations of equal feeble-mindedness and absurdity for different reasons you may be asking why you exist. They all bash "the moral enthusiasts", God, and anyone that is trying to do something with their life. Excuse me, ladies and gentlemen! Does this explanation of what your life is not disappoint you? Don't you want to have a purpose? Don't you want to know the TRUTH?
Have I got good news for you! You are NOT useless! Or worthless.
If you're wondering about the meaning of life, read the book of Ecclesiastes. If you think life is meaningless, you will find that many elements of life are. Wisdom, pleasures, toils, advancement. Some of these things ARE life to many people. If you live for them, your life is meaningless. But in the last two verses of Ecclesiastes, Solomon states the conclusion of the matter, the meaning of life.
"Fear God and keep his commandments,
for this is the whole duty of man.
For God will bring every deed into judgement,
including every hidden thing,
whether it is good or evil."
That is the duty of man. Fear God and keep his commandments! Trust and obey! It's not, "do what makes you happy" because pleasure is meaningless as well. You will only find fulfillment if you carry out God's plan for your life. He's excited about it! You can be useful to God of all things! Are you ready to find life and find it more abundantly? Do justice, love mercy, walk humbly with your God. And you are not worthless - to God you are a precious, special gem. There is so much more the Bible has to say to you - why don't you give it a shot?