You are correct that it depends on circumstances. My comment assumes working on a software project for a longer duration and also that the project is non-trivia

You are correct that it depends on circumstances. My comment assumes working on a software project for a longer duration and also that the project is non-trivial. Regarding your 80/20 comment I would say that this is true regarding features. I.e., quality attributes that the external world sees. My comment is about internal quality. So, let us say we have the 80/20 mindset and determine that features A, B, C, D, and, E belong to the 20% that we want to deliver and features F through Z end up on the backlog, perhaps to never be seen again. With insufficient internal quality it happens that the first and second version of feature C actually do not work, but fortunately feature C works the third time. Then feature D breaks feature A, but this can be fixed. After that feature E breaks C again, distressing the customer to no end because this is the third time that they have to report that feature C is not working and they already were a bit irritated that feature A broke.