How sad for that child! Of course I would like my kids to bring all A's home but I'm happy with the best they can get as long as they try. If a C is the best they can do, I'm happy with that but if they get a C because they goof off , that's another story. My DD last year thought the same thing, that I was going to be upset because she got a B+ in Math. My dd always strives for perfection which scares the heck out of me because she puts way too much pressure on herself.
Neither one of us puts any pressure on any of the children , we simply tell them to do the best they can and give them the tools to do so, we have been blessed so far.