Reminds me of that Rick and Morty episode with the perfectly level floor. At a certain point in reality you also would need perfect tools to check if something is perfect. Measuring the stick so to speak. I believe it is theoretically possible to get perfect angles, but keeping it that way might be a challenge outside of a vacuum. As a thought experiment, if you take your arm, hold it straight, then bend it, for 1 picosecond or something, wouldn't the angle of your arm be exactly 180.000~°, 90.000~°, etc, as it is bending?