10 - Great : Appeals to me in the best way possible, I would highly recommend a watch
9 - Very Good : Positives highly exceed any negatives, I would recommend a watch to anyone
8 - Good : Positives exceed negatives, a solid watch and I would recommend to anyone who likes said anime's genre(s)
7 - Above Average : Has flaws, but not enough to make it not enjoyable most of the time. Would still recommend to anyone who likes said genre(s), but with lesser priority.
6 - Average : Capable of being enjoyable at times, but is consistently no more than passable. Time could be better spent on other things.
5 - Below Average : Either does nothing to attempt to be appealing, or fails at it.
4 - Bad : Not good, I would recommend you stay away
3 - Awful : Extremely flawed, has far more negatives than positives. Generally "so bad it's good". Watch with a friend to laugh at it.
2 - Abysmal : As if they're doing it on purpose. Only worth watching with friends for a laugh.
1 - Insult to the medium
Same applies to manga, but I only really read the manga of anime I liked or manga that were recommended to me by friends, so expect the scores to be generally higher overall for them. 6 is my average because I believe that the average show should at least be more good than bad, and that's what the people who made them do/should strive to be doing.