Let's say you go to a playground with a friend, sit down, and start colliding balls with each other. If you do this long enough, and measure velocities precisely enough, you will eventually invent Newtonian mechanics.
You become very happy with your new knowledge, and start applying to various things, like electrons, calculationg their speed after passing a certain potential. You are indeed satisfied with the results, but the night starts falling, so you say goodbye to your friend, and head home.
Your friend, who happens to have a synchrotron at home, decides to test your theoretical results experimentally, and he finds out that your calculations doesn't fit with the results - electrons accelerate slower and slower as they approach a certain speed, which seems to be a limit for them.
The next day you meet again, and have an intense debate until you are no longer friends anymore. You are both convinced that you made no mistakes and have the correct results.
So, what just happened? In short, you disregarded the empirical confirmation of your results. To be a bit more verbose, you applied your theory outside it's realm of applicability - which must be determined empirically. No matter how long you push balls, drive cars, do ordinary things at ordinary velocities, or just sit in an armchair thinking, you won't find out that space is curved, the speed at which information can spread is limited by the speed of light, and the transformation connecting inertial frames of references is not the Galilei, but the Lorentz transformation (unless you are Henry Poincaré - no, kidding, the Michelson Morley experment is still needed).
So, what I want to say is this: saying that because chairs have a creator, the universe must also had a creator is making an unjustified logical jump and using this poor quality logic outside it's narrow realm of applicability. Claiming that this creator is the specific god you worship is just a minor fallacy compared to this.