Cool, your score was 11-2-8. Good job! But, if you have 3.8 cs/min, a total of 4 wards placed, and took 0 towers, you aren't getting an S. It's League, not Call of Duty team deathmatch.
So PLEASE stop spamming the boards with your matches.
Edit: Yes, it's your. I had a different title and didn't double check after changing some of it.
Edit 2: I'm tired of seeing the "But I think getting kills and carrying the team is more important than afk farming." Nobody said it wasn't. CS isn't the only factor. But, you are judged against other players playing that champion/role. So, if you're playing some stupid easy pubstomp champ (riven), you getting a lot of kills is not that impressive. As a lot of players do that. The difference is, those other players get a lot of kills AND a lot of CS. That's why they get the S and you don't. If someone else does everything you do, AND then gets a lot cs, you aren't going to be given the highest rating.
Edit 3: Supports. You are judged against other supports. So no, not getting cs as Janna doesn't screw your rating. Nice memes, though.
Edit 4: This is an example. As you see here, the Ashe has the highest KDA, the most damage dealt in the game, the most wards placed in the game, and still manages to have 10 cs/min. That is an S performance. If you don't do everything well, you are not going to get your S. Since there are players that do everything well in some games.