With a very small margin for error, I think I can recite every course in which I earned a B in my undergraduate and graduate degrees. Some were lack of diligence (as in I just didn't do quite enough work and/or study, in the inevitable trade-offs most students make), some were genuinely my best effort, and some were a complete surprise, where I thought I'd nailed an A until I discovered the reality. Many years later, I can honestly say that none of the B grades were a threat to my career or a limitation on my quality of life.
Each semester, the joy of electronic communication (aka email) allows students to petition for various grade-enhancing indulgences, without the discomfort or inconvenience of an office visit and eye contact. Some of the requests are charming, some are amusing, some contain more than a modicum of entitlement--they came to class regularly, they turned in all their assignments, they tried really hard, they deserve an A. I think it's the entitlement, more than anything else, that troubles me.
Doing the minimum (which, in my mind, includes turning in assignments and coming to class) does not guarantee an A, a grade intended to differentiate the top 10%. In fact, doing the minimum would (in a perfect world) garner an average grade. On some level, most students know this. What they often worry about, however, is losing GPA-contingent scholarship money or dropping off some variation of the Dean's List. Somehow, both the students and the academic community have lost sight of the real goal, which should be learning. But that opens an entirely different discourse about how (and why) we use the methods we use to assess learning.