1. Horrific. I couldn't find anything redeeming about these shows whatsoever. I more than likely found them to be so bad they were insulting.
2-3: Terrible. Overall I disliked these shows, and only small bits of enjoyment here and there. Not recommended at all.
4: Disappointing. These shows I usually found had an interesting concept or something to that extent, but turned out to be disappointing in the end for me.
5: Average. Some things I liked, some things I disliked. I didn't feel strongly either way about these shows.
6: Decent. I enjoyed these shows more than not, and found them to be fairly entertaining. Worth a watch, but there's plenty of others I liked much better.
7-8: Great. I enjoyed these shows significantly, and are definitely worthy of a strong recommendation.
9-10: Fantastic. I enjoyed these shows so much that I may be prone to nonsensical outbursts of fangirlism. I can't recommend these shows enough, and probably marathoned them through to the end and watched them several times over as well.
The star system in my anime list essentially functions in the same manner. Example: 3.5/5 stars is equal to a 7/10.