Not all things have to have a reason for existing, in fact not all things can have such reason - the very concept of something having a reason is just a product

Not all things have to have a reason for existing, in fact not all things can have such reason - the very concept of something having a reason is just a product of our utilitarian view of the world and one that can not be applied infinitely; at the end something has to exist for its own sake. My goto metaphor for life is making a picture with a paint that evaporates from the canvas immediately after having made the last stroke - it will not produce a dent in the universe but nevertheless you can take pleasure in the process of painting it. Before I die I would like to have the feeling that I expressed everything I am capable of expressing, in terms of emotions, thoughts, writings, inventions, so that there is no reason any more for me to continue living anyway. My capabilities are definitely finite, so it should be attainable.