10-omg best anime ever.
9-Incredible but for whatever reason not quite impressive enough for a 10.
8-Very good or great.
7-This was good but not amazing.
6-This was reasonably decent/entertaining.
5-I enjoyed watching this, but barely.
4-I didn't like this.
3-Some good aspects, but very bad as a whole.
2-Almost completely irredeemable
1-I sincerely hope nothing nowadays manages to get this rating.
Also something worth mentioning is that in the case of comedies I'm typically more fond of the show than the numerical rating might indicate.