When I read some variation of the title as a comment for one of my reviews, I automatically lose respect for the poster. This seemingly innocuous phrase is actually one of the most ignorant things that people commonly say, right down there with "I disagree completely. Horrible review."
But let's start at the beginning. A common misconception is that, say, a "7" has some real world meaning. This is not true. For some people's scales a 7 is great, while for others it's "average" or even bad. As such, for a person with one anime under his belt, it almost doesn't matter what he rates it. A "1" will mean he disliked it and a "10" will mean he liked it, but otherwise there is very little to be interpreted. Ultimately, all ratings are arbitrary.
And yet, we find ourselves assigning numbers to anime. In some ways this is absurd, as we find ourselves having discussions like these where there is no clear consensus on what a "7" actually means. The simple truth is, a single score by itself is meaningless - the score only gains value when compared to other scores. Because we are assigning numbers to something that is not quantifiable, EVERY scoring system is arbitrary.
Thus, the importance is not "accuracy" as some seem to believe because that is impossible anyway. Rather, the most important thing is to create an arbitrary system that gives people a clear view of your opinions.
That is why I try to have a normal-ish distribution for my scores - so that the anime I thought were especially horrible or especially good stand out from the rest. More specifically, if I think two anime are "ok," it matters much less whether I think one is better than the other, as they're both largely forgettable. However, if I actively like two anime, it matters very much if think one is "good" while the other is "great." It matters even more if I think one is "great" while the other is "amazing."
So do I believe that my enjoyment follows a normal distribution? No, not at all. Enjoyment does not actually follow any distribution. It is not quantifiable. If you ask someone how much they enjoyed their day, they can't spit out a number. They'll just say something general like "it was good." Remember, the important part is to differentiate which anime I enjoyed more than others.
That is part of the reason why "the sound deserves at least an 8" is so inane. For one, it implies that there is some "true" meaning to whatever an 8 means, when in fact its only objective meaning is that it is higher than 7 and lower than 9. For another, it ignores the *actually* meaningful part of the review: the text.
I try a great deal for my scores to be internally consistent (well, except sound. Who gives a fuck about sound?), because I want people to know that I enjoyed Monster more than I enjoyed Ouran High School Club. But that, in my view, is the extent of the usefulness of ratings. They are a relative measure, nothing more.
The next time you feel like commenting on a score, instead look at the points in the review and comment on those. The resulting discussion will be infinitely more meaningful. If you don't, I won't rate your comment higher than a 67 out of 141.