•To my eyes, it's quite difficult to rate anime objectively.
In most cases, you have to separate two types of anime:
_Those you're watching in one time, shows you began when they're already finished, and that you can watch entirely if you want.
_And those you're watching episode by episode, every week, from spring, winter... falling.
Actually, you can't rate the same way a show that you've been hyped, and that you've watched in a row than a show that you've been waiting every week to see next episode.
You always be more objective with a show that you'll follow every week.
According to me, it's obvious that you'll rate better a show (better than the score he really deserve) when you're hyped by and when you've been watching it in few days. It's normal.
That's why I consider that few of my rates could be higher than they have to be.
(and that's also easier to stop or watch entirely a show week by week, than in a row, because you can make some pauses, and give more chances to it...)
•How I rate for mangas?
9: One of the best manga I've ever read. Must read & must have.
7: Very good.
4: Average (-) (-)
2: Very Bad
1: Piece of shit
Nevertheless, it's not because lot of mangas have the same score, that I put them on the same level. Indeed, for exemple, I've rather much enjoyed "Inu Yasha" than "Naruto" by I give them both a 6. Because of the fact that I consider them as "good", not "average", not "very good". Just "good".