The only way you can actually believe Flat earth is if you are a conspiracy theorist, thinking every government and scientist alive wants to lie to everyone for no god damn reason at all. (they gain nothing from people thinking the earth is flat or spherical, they lose money trying to hide it however)

if you have never stood by the ocean, or atop a large mountain (or peak),
if you have never flown in an airplane (especially trans Atlantic flights)
if you are unfamiliar with time, and time zones and why they exist
are willing to believe anything
are far to lazy to try one of the numerous experiments that prove the earth is a sphere
and have the IQ of the average potato.