I find "giving" grades as a teacher to be as troublesome as getting them when I was a student. Alfie Kohn (1999) in his book Punished by Rewards: The Trouble with Gold Stars, Incentive Plans, A's, Praise, and Other Bribes argues, based on solid research, that rewards, such as grades, often undermine intrinsic motivation (p. 148), which is key to a substantive long-term learning. This counterproductive practice persists because our educational system attempts to do two things that are often at odds with one another: facilitating learning and sorting students (p. 202). I've seen this in my own classroom. Some of the brightest students, and no doubt the most consistent "performers," have expressed a strong distaste for open ended assignments. Asking them to propose a topic that interests them is far too frightening relative to the more remedial types of tasks they have clearly mastered. As Kohn notes, "when we are working for reward, we do exactly what is necessary and no more" (p. 63); this isn't necessarily because of laziness, it also avoids the risk of hurting one's GPA. On the flipside I've seen students with a lot of potential but also significant challenges (perhaps English isn't their first language, their previous education wasn't as rigorous, illness, financial constraints, etc.) become demoralized with a poor grade. Few things are as frustrating as seeing motivated students and a positive classroom culture taking hits because of grades. Nor do I want to be in that position of judging students' circumstances: perhaps Solomon could fairly judge between genuine illness, family emergency, forced overtime, or a hangover -- but I can't.
I'm not completely comfortable with my present approach, perhaps one day I will become an "easy" grader and submit all "A"s except for the most obviously negligent, but this is what I work with now: explicit criteria and early feedback.
According to the standards of my department, which are quite useful and comprehensive, an "A" is a reflection of an "An Outstanding Student" whose "Writing demonstrates impressive understanding of readings, discussions, themes and ideas. Written work is fluid, clear, analytical, well-organized and grammatically polished. Reasoning and logic are well-grounded and examples precise." My present understanding of an "A" is also informed by my experience as a Ph.D. student. I expect I've been a bit of a "grade grubber" myself, though fortunately willing to take risks to pursue my interests. One of my greatest disappointments in my nearly 10 years of classes, but not my lowest grade, was an "A-" in a historical methods course. I loved the course, adored the professor, and invested a lot of myself in the research and final paper. But at the outset the professor said he only gave an "A" to those papers he could see being accepted for publication and he was true to his word. After a few days I could admit to myself that my paper was not yet at that level, my research and thinking weren't developed enough yet, and I learned I was not alone -- in fact I was in the vast majority. (It's a sad truth of how we can feel better or worse about ourselves through comparison with others! A colleague of mine once cynically captured this with a sentiment that, "every time a friend of mine succeeds I die a little inside.")
In any case, I use a similar threshold in undergraduate classes. I don't "give" grades, I evaluate performance according to the departmental criteria. I don't grade on a curve, but I do make sure my expectations are reasonable by first reviewing the range of performance. An "A" is truly outstanding, something I could use as an exemplar in future courses or even recommend to someone interested in the topic. An "A-" fell little short and could be a "A" with a few small tweaks. A "B" is a reflection of good work, a "C" of "fair" work. I do want to be humane, some professors have cut me slack in the past, but also fair. It is not at all uncommon that at the end of the semester when I'm porting grades from my spreadsheet to the bubbles of the Scantron to want to bump a grade, but I fear this may be favoritism, so I don't.
Grading sucks, but it's a requirement of the job, and I am not sure of what the alternatives would be.