Level?

Had a discussion today at work about "level". With most construction projects, you try to make your work as level as possible. Sometimes it's impossible depending on prior circumstances. In that case, you try to make it "flat". Now "flat" and "level" are 2 different things. "Flat" can be out of level, but "level" has to be flat. Seems "flat" can do whatever it wants, but "level" is held to certain physical laws of the universe that it's not allowed to break. Now it was explained to me that "level" has to be parallel with the horizon, and that water seeks its own level. Think about this. If the earth is round, can we actually make something "level"? If water seeks its own level, why does it follow the curve of the earth? I'm sure there's some scientific remedy involving gravity and the tensile strength of water and blah, blah, blah. But if I have one leg shorter than the other, this is all a bunch of hooey, and I'm all in favor of "flat"!