I think the earth is flat
Why do you think the Earth is flat?
I've observed more than enough things "illustrating the fact"
It's okay to question ideas that seem doubtful, but believing in conspiracy theories that are proven false is unhealthy. Maybe you can work on your critical researching skills so that you are better able to identify sources that are peddling misinformation.
I'll just keep believing in the flat earth.
Nobody can stop you from believing in these things if you are so determined, but at the same time, anyone can sit on a beach and watch a ship sail away.  When a ship reaches the horizon, it slowly droops down as it curves around the Earth.  People who recognize this simple fact will have a right to think you are foolish if you do not also accept it.