If some deity created the universe to make a place for humans,
it took its own sweet time to do an insignificant thing. Estimates with a high degree of confidence put the origins of the existing universe at about 14-15 billion years ago in the past of existing time. Human beings, or some beings close to being human, didn't appear in that universe until about 2 million years ago. Human civilization is just a few thousand years old, at best.
How long will humans remain in the universe? That's a difficult question to answer. The answer, I suppose, is: "Well, it depends." A massive asteroid we don't know exists could clear our tiny little watery ball of a planet of humans in the blink of an eye, and such an event has happened before, so we know it's possible.
Some semblance of humanity has existed for about 2 million years, out of the double digit billions of years of the universe's existence. We are insignificant. Massively insignificant, really.
So, why would some deity take the trouble to create an entire universe for humans to inhabit for a brief flash of time? I can't imagine.
There are and have been as many creation myths as there have been cultures in humanity's brief existence. Some of them seem ludicrous to most of us. All of them seem ludicrous to some of us. Whether it's "turtles all the way down" or a deity doing all that creating in six metaphorical days before taking a rest, it flies in the face of actual physical evidence. The universe we know has been here for billions of years. We have been here for a couple of million, at most.
At one time, I suppose, the need to believe that an omnipotent deity acted as the "creator" existed. Some explanation was necessary. Humans are curious primates. That time has passed, and the "creators" that have been imagined to provide that explanation are no longer needed. We know stuff now that we couldn't have known in the past. We'll know more stuff in the future. But we already know enough stuff to make all those creation myths seem pretty silly, I think.
Moving on through my brief time...
= new reply since forum marked as read
We're not, but we need to think we are. That's the grand joke, really. We're just smart enough to understand the concept of significance, and we think ourselves to be of some importance.
And here we are on the third planet in orbit around an insignificant star, on one wing of a galaxy with billions of stars, in a cluster of galaxies, in a universe that is so large that we are invisible to virtually all of it.
But, we think we're significant enough to get special attention from whatever created this amazing existence. C'est pour rire, as another member of this group might say. We need to be significant so badly that we created a "Creator" to explain why we are significant somehow. It's hilarious, really.
I'm significant to myself and a few other humans. That's it. That's enough, really. I don't pretend to be more than what I am - a walking cell colony with a brain that gets a few decades of existence. While I can conceive of more than that, my conception doesn't really matter, in the greater scheme of things. 
