when you spend several days on a specific part, you want to make sure you get it right. then, when you spend a week on it, it'd better be almost perfect. of course, it's complexity grows when you spend that much time on it, as well. so, the importance of getting it right increases. then, when you've spent two weeks on it you're not satisfied with anything less than an impossible ideal.
then, when you're struggling with old age, and you're still cursing the machine for not getting it right, you shit in your diaper and realize the futility of the whole endeavour.
i'm just about done convincing myself this is perfect.