Sails around the world can be described by
curvature, not necessarily a
round/ball plane of existence.
A better example would be to be a frequent flyer, and look out at the little arrays of light... then realize at near cruising altitude, these little arrays of light on flat(ish) terrain are actually
cities and small towns.
If you zoom in on the old "boat over the horizon", we will see tat the boat is actually still traveling straight - it never actually curves over the horizon (it is an optical illusion created by the interaction of light and the curvature of the water plane.)
(Note: I am not saying this is proof of a flat planar earth).
People have the intellectual right to question whatever they want to question - especially given the
history of deception by all institutions. The disdain and scoffing shows the limited capacity of the person commenting - which is fine. Not everyone has the patience or willingness to entertain
everything without necessarily accepting it... not everyone is supposed to.