[1] is part of the basic domain knowledge that makes one competent. E.g., any programmer who deals with US PII should also know that social security number coll

[1] is part of the basic domain knowledge that makes one competent. E.g., any programmer who deals with US PII should also know that social security number collisions exist even though nobody on the team has struggled with it. Your coworkers' personal experiences are not the only or best way to learn about users' problems, because not only are they a very small sample but they are self-selected nerds and inherently unlike most users (unless you sell programming tools). [2] is a product design decision, not a programmer's ignorant error. "A product should side with a child against their legal guardian who actually paid for the product" is by no means the consensus across all cultures.