I'll give it a go just for fun.
1. The ground appears flat on small scales. I don't understand how circles work, therefore Earth is flat.
2. Some unnamed law of physics states that the surface of a liquid must be flat. A round Earth requires the surface of the oceans to be curved, therefore Earth is flat.
3. The Sun, Moon, and other celestial bodies look like two-dimensional circles. I don't understand perspective, therefore Earth is flat.
4. I don't understand what a composite image is, but it sounds like a NASA conspiracy, therefore Earth is flat.
5. I have never bothered to look for unaltered photographs of Earth, therefore Earth is flat.
6. I don't understand how gravity works and I have never heard of the Cavendish experiment, therefore Earth is flat.
7. Something about aether, therefore Earth is flat.
8. The concept of a non-aerodynamic object floating around the planet without falling seems ridiculous to me. I don't understand vacuum, therefore Earth is flat.
9. If the planet was round and spinning it would fling us all off. I have never actually done the math to verify this myself, but it sounds about right to me. I don't understand uniform circular motion, therefore Earth is flat.
10. You are a government shill, therefore Earth is flat.
QED.