I aim to maximize my GPA for employment and grad school reasons, so I try to get as close to an A as I can, multiplied by six.
I try to as well, but once I literally rage quit an assignment after spending a month on it and not going anywhere with it, and this was this semester.
I mean, I often give up on papers before they're "perfect" in my--or my professors' eyes--and there are always assignment produced below the optimal level of quality, but I try to do it within a certain margin of "likely to produce an acceptable result".