There is no meaning of existence. Our existence, that is to say not just creatures but intelligent thinking ones, is really a huge improbability, but due to the size of the universe we know it has happened at least once!
So we’re a fluke, pretty much. An accident. What is the purpose of an accident? It just happens, there is no purpose. And the same is true with life. There is no meaning to existence.
That said, given that there is no meaning, humanity has generally speaking done a pretty good job at striving towards the future. We love knowledge, we love learning about ourselves and why we are here and what the universe really is. Then again some people love cooking and eating Italian food with the same passion. Good on them!
My outlook is this: I exist, so I’m gonna take advantage of it. I communicate with other intelligent beings, like what I’m doing right now. I learn and experiment and explore the world around me, as well as observing explorations that I cannot do myself (yet), like watching documentaries about Antarctica or videos of Neil Armstrong in space. I create art, I take huge pride in knowing that despite our huge population, the item I have created with my own is completely unique and unlike any other object in the world. I spend a lot of time thinking and reflecting on my life in various ways, including talking here on Fluther, writing blog posts, thinking deep thoughts, and being with friends.
This outlook has helped me to deal with negativity in the world as well. Since life is a fluke and I don’t believe in any sort of afterlife, this life is the only one I have. I don’t want to waste it being angry at people, holding grudges, or doing things I don’t love to do.