When you do earth curvature measurements and there is no curve, and witness hundreds of like measurements with the same results, it's not unreasonable to assume there is no curve.
When the record long-distance photography picture shows things that would be impossible on a ball as we are told it is, it's not unreasonable to assume there is no curve.
When the record distance microwave transmission was completed at a distance impossible on the globe due to line of sight, it's not unreasonable to assume there is no curve.
When people are using infrared video equipment and are capturing the bases of mountains 1,200 miles away when the peak of it should have been hidden under 120 miles of globe curve, it's not unreasonable to assume there is no curve.
When you learn that science attempted multiple times to prove the movement of the earth, but failed and had to create the concepts of special relativity and Lorentz contraction to simulate motion, it's not unreasonable to assume the earth isn't in motion.
When science has proven through experimentation that the observed motion between the earth and the stars is because the stars are the objects in motion and not the earth, it's not unreasonable to assume the earth isn't in motion.
When Stephen Hawking does an earth curvature special to 'prove' the curve and has to fabricate his measurements, it's not unreasonable to assume he couldn't find a curve.
So, when everyone gets on these threads and exclaims flat-earthers are stupid because {insert list here} wouldn't work on a flat earth, the truth is, it's already working on a flat earth, you just don't realize it yet. We have so much evidence on our side, it isn't even funny. But you have pictures of a ball, so there's that.