How did I play Ori got 22/8/9 got an A and Diana 14/8/10 got an S? Riot is a fair game? Seriously?

I think you've got the wrong sub-board, mate.

http://boards.na.leagueoflegends.com/en/c/gameplay-balance

time in game, cs, towers, roles played, objectives assited and taken, dragons and barons in jg kd means alot less than people think

Maybe because she flame horizoned you and she was the freaking jungler.

ok, outside of kills.

• objectives taken: dragons, other enemy camp, baron, herald? herald does contribute quite a bit to a s-rank for a jungler.
• CS?
• ward used, wards destroyed?

if you excel in all of those charts by the end then you get an s rank.

To add what other people have been saying, you should also take into account the champions you are playing. I probably see a lot more Orianna players than i do Diana. If a lot more people are playing a certain champion it basically makes getting a higher ranking that much more difficult.

How the actual fck are people still ignorant about the grading system? Why...no seriously, why are we still seeing these types of posts?

Ridiculous!