Good design is invisible—when it works, nobody notices, and when it fails, everyone blames the user. I've spent six years as a product designer, and I keep hearing that 'design is subjective,' but that's just an excuse for sloppy thinking. If a door needs a 'push' sign, that's a design failure, not a user error. The best interfaces explain themselves in a millisecond, and anything less is decoration, not design.