1. Billions of people have, myself included. I can detect a degree of curvature at some beaches with a wide enough view. I have seen the obvious curvature from planes. I believe a majority of RE'ers will agree with this assessment.
I've looked at the ocean. I've never seen any curvature.
I've been in a plane. I've never seen any curvature.
TheEngineer, a pilot who posts on this forum, tells us that the horizon of the earth is not curved from the air.
So its two people's inability to see something that's hard to detect that you are using for evidence?
Keep in mind, seeing the curvature requires a very wide angle view, especially when close to the ground. Plane cockpits and windows are small so you would have to be increasingly higher to see curvature through the glass.
2. Have you ever seen a flat Earth, ignoring the flawed experiment of looking at a locally linear section of the Earth?
I don't see why any experiments should be "ignored" just because you think it should be.
It should be discounted because it is
flawed, not because I have a problem with it. Keep reading...
Keep in mind that by definition, evidence has to support one theory and not another mutually exclusive theory.
See?
I just see a flat plane stretching in every direction.
So now that you see a 'flat' plane extending out from around you, are you revoking 'the sinking ship and bendy light' argument?