Another point in support of this is that buildings tend to get away with more minor bugs than software does. Walls usually have a subtle bow to them, toilets don't have to fail gracefully if the sewage network gets backed up, doors get installed the wrong direction, there are gaps behind the cabinets, light switches get wired around odd corners, etc. So long as the building can stand up in an earthquake and looks good enough to sell, that's usually the end of it. Software, on the other hand, has an air of imperative perfection. If it is even slightly wrong or ugly, it must be entirely wrong. I feel that way myself, and I must sometimes throttle my impulse to fix it indefinitely so that I can meet a business need in time.