http://rationalwiki.org/wiki/Occam's_razor^link for people who don't get it
"Ocams's razor", witch in essence says that the theory that requires the least assumptions is
usually the more correct one (to be fair, it is more complex than that, but that's what the link is for)
now lets take a look at all the assumptions we have to make for round earth:
1: that science is (mostly) right about gravity, astronomy, and physics
and all the assumptions we have to make for flat earth:
1:that all the governments of the world have organised a conspiracy to convenience the masses of the earths (false) roundness
2:that the earth is either accelerating constantly in a blatant middle finger to thermodynamics, or that "down" is just the intrinsic direction of the universe
3: that the millions of people lied or were wrong about the direction that a hurricane/tornado was spinning
4: that thousands of people who have looked through telescopes and have seen satellites and other planets lied
5: that the millions of people who have looked at the horizon and have seen the curvature of the earth were wrong, or that light "bends"