The French philosopher, Voltaire, said that if God did not exist it would be necessary to invent Him. He was probably being cynical, but it sounds quite true to me. Human beings do NOT have control over many things around them. There are times when there is nothing they can do to help themselves, or should I say we can do to help ourselves. And when those times arrive it is impossible not to wish there was some higher being to yell out to for help. It gets said, some people treat God like the fire brigade: they only call Him when they need help. But that's another issue.
For centuries, human minds could not understand a lot of the natural events and forces around them. They could not know what caused some diseases, or the changing seasons. When you can't understand something, your may be helpless in the face of it. It can also leave people thinking there must be some awesome power behind it that you might need to make peace with. But then as scientific understanding grew, the human race understood the world and the universe better, from a rational point of view, and some of them said, well, we don't need God. We can explain and control it ourselves.
Remember what they said about the Titanic: "Even God cannot sink this ship" or words to that effect. Well, guess what! So even if the human race can do awesome things, we still can't control the world the way we might wish. The unfortunate victims earthquake in China, storm surge in Burma, floods in the U.S. and drought in Australia can tell you that.
Humans can do a great deal more than they once could to help themselves, but they can't guarantee much at all. Once in a while we find that out the hard way.
The saying goes, there are no atheists on a battle field, or a sinking ship, or even a ship in trouble in a bad storm. I can't confirm that from personal experience but I can remember people who call themselves atheists saying "Oh God!" in moments of panic, and sounding as if they meant it.
We need God. Some people just won't admit it. And if God wasn't there, and we were at the mercy of whatever can happen in the world...