fun fact: the length to width ratio of ISO 216, √2:1, is the same ratio as the tritone in an equal tempered 12-tone musical scale. If you fold A4 paper in half, you get a piece of paper with the same length to width ratio as before; analogously, if you invert a tritone, you get another tritone.
You’re not alone
https://youtu.be/X34ZmkeZDos