My first slab pour had us leveling concrete with a 2x4 and eyeballs.
Back then, we didn't have laser levels, so we just guessed and hoped for the best. Now with precise tools, it's way easier, but that old way led to some funny slopes. What's the goofiest method you ever saw for getting a floor flat?
Yeah that "floor that drained itself" sounds about right for my level of DIY. Last time I tried anything with pipes I just moved the water to a different, worse place.