This is taken from the ACA website:
Q: Don't atheists have basically empty, meaningless lives, when they don't believe that there is any higher power out there?
A: Nope. We don't think that the world is an empty, meaningless place, even though we don't think a god designed it. We think the world is a fascinating, wonderful, interesting place, and we enjoy living in it. Now, you may think that it's impossible to "really" enjoy this world without believing of God as the designer. We don't feel that way.
Suppose you are walking in a beautiful garden with a friend, and your friend says, "I heard there are fairies living in this garden!" You tell your friend that you don't see any fairies, and you don't see any particular reason to believe that these fairies are there. You are just enjoying the garden. But your friend insists: "How can you enjoy this place if you don't believe in fairies?"
Unless you're a little kid, you would probably feel that your friend missed the point. Here you are, enjoying a nice day and great scenery, and your friend is trying to convince you to stop enjoying the garden the way it really is. He is telling you that you have to make something up, which isn't real as far as you can see, or else you don't have as much of an appreciation of the garden as he does.
In fact it is probably the other way around. It's a fine thing to have an imagination, but it seems like your friend is cheapening the experience, because he can't just enjoy something beautiful for its own sake.
The world has a lot of things to enjoy in it. Food, music, a well-told story, romance, sex, physical activity, the outdoors, the feeling of solving a difficult puzzle... just to name a few. These are things that most people enjoy on a day-to-day basis. And we don't appreciate the world around us any less for not thinking that those things come from God.
Also, it's not like there are no mysterious unknowns or "greater forces" right here in the physical universe. Most likely we will never know everything there is to know about this vast universe or our past. Who really understands quantum mechanics? Are there parallel universes out there? Are they accessible to us? Is time travel possible? Can we find a better way to generate our own energy before our sun burns out billions of years from now? These are all very big mysteries. One of life's great pleasures is applying your mind to solving hard questions like these. Learning is fun. Knowledge is fun. So it seems likely that we will never run out of things to enjoy in that sense.
You may have plenty of good reasons for believing in God, but if you think it's bad to be an atheist because atheists lead a cold, barren, loveless, uninteresting life, you are really kidding yourself.
I am not a theist, but just out of curiosity how can you objectively justify this answer? No body cares about how you feel reality is, but what is objectively true. You can intellectualize and rationalize all you want but appealing to emotion is fallacious. So, why is life meaningful because we feel it is or we know it is?