Alright, I'll bite into this conversation. Lets then assume that the Earth IS flat. That we have been lied to by every social and educational system in our Western Civilization. If you live near the sea my challenge to you then is to see any and every boat/ship off the shore and carefully observe what happens to them as they go further and further away from sea shore and beaches. Another neat thing using the beach is during Sun set. As the sun is off the horizon halfway when you can see only half of the sun, stand where you are, and simply lay down and see if your perspective of the sun changes. Since you're already at Sea Level (being at the beach) its not the same as being on top of the Empire State Building, or Sears Tower, seeing the sunset, then quickly go down the the ground floor to see it again a second time. Carefully observe such a thing. It's pretty cool, actually.
Or..
if you are in a land lock area: find the most flat out non-plateau area you can travel to (because who needs to fall off a cliff? no bueno). Take one other person with you. Each have a measuring tool to measure accurately the distance, and a Watch for telling of time. Sun screen, plenty of water, a map of the region, communication device, and food are optional. Now, with a possible GPS system and the required equipment, have your partner simply walk away from you until you can't see them anymore. Then discover the distance apart from the point of being next to each other to the point where you could no longer see them, where they just "disappear." Early morning is more advisable because of the cooler weather, and time with natural sunlight when you start.
A flat Earth makes it impossible to for them to "disappear," without falling off the Earth, as they travel further and further away from you. And be prepared that it may take 22miles (or 35.4 km if that's what you're use to) for such a "disappearance" from happening. Nevertheless, I challenge you to do this experiment.
My point is: We don't need NASA or US gov't telling us if the Earth is flat or not, or whether they're lying to us in some grand conspiracy theory. Not when, in this case, we have some practical, relatively super cheap, experiments we can do to test out the scientific theory. Best of luck! Have fun discovering and learning. I didn't write all of this to patronize you but rather to equip you for better understanding, and to see it for yourself. That in this regard, it is not some giant conspiracy theory.
Peace! and best of luck!!!