10; Absolute masterpiece, besides being a close to perfect anime - it has to have some extraordinary appeal to me to gain this score.
9; Very strong with close to perfection. It has to do something unique and outclass other series that may or may not seem similar.
8; A very solid anime, which is both enjoyable and objectively well done
7; Solid stuff, for instance very good comedies with basically no story will land here. Also other good series that doesn't take it to the unique level with few flaws will get this score.
6; A good anime, may have been fun and entertaining - but not quite taking it to another level than that. Could be cute or appealing in some other way, without being very deep.
5; Decent stuff, very ordinary that can be found a lot - possibly trying too hard to be something else, or just a very ordinary comedy, that doesn't succeed very well on a higher level (probably bad re-watch value)
4; A somewhat bad anime, which has a few good moments, but the overall picture is that it could be done quite a lot better.
3; At this point it is pretty much not worth watching. Most likely everything about the anime seems like a bother - especially the characters in it.
2; Just very awful, not very enjoyable and not trying to accomplish anything. Just plain bad.
1; Disastrously bad, trying really hard to entertain, but it simply is pure garbage. Characters dull, story not-existent - and possibly animation being very poor. It is as unlikely to find a '1' as it is to find a '10'