Why does anything at all exist?

[Hezekiah]

I believe that by asking, "why" you're assuming the universe and everything that exists, exists for a reason. And if you're asking for reason you're assuming there is meaning. And if you're assuming there is meaning, you are suggesting that there was something to give it meaning (since you can't have meaning without a mind to endow it). So if you're looking for a theistic answer you'll most likely get something along the lines of "God created everything so that he could enjoy his creation". If you're looking for a specific reason why he would want to enjoy his creation then you are jumping into types of thiestic worldviews (Christian, Buddhist, and Islam), and that is something you should explore for yourself.