Got my first S Rank. In the most amusing way possible.
Not gonna spoiler this cause it's a meaningless not important mission.
I did the mission with the 3 generals meeting where you have to kill them all. Up to this point I've done every single mission sneaky and non-lethal because I'm super lame and terribad at it and hate myself. So I'm sneaking in and see the car pull up and identify one of the generals. Well, he sees me and sends some dude to go find me. I manage to sneak away and follow the general's progress and sneak up on the building he goes into and hide across from the entrance around the side of another building. I begin to listen to his conversation.
Well, in my scouting I had not noticed a random dude who walks right in front of me and I reflex action and tranq him in the head. Somehow, however, it alerts the general and the other two guys inside the building. Panicking and not knowing what to do, since I didn't wanna restart at that point, I decide "Fuck it" and equip a grenade. The general opens the door and I lob the grenade it. They all panic and stand there as it explodes them into pieces. Well that's one general down now to-
Mission Objective Completed 1/7
Mission Objective Completed 2/7
Mission Objective Completed 3/7
Ocelot stumbles over himself repeating the same thing 3 times and alerting me that I killed a general as I ran cackling out of the village.
Run out of the Hot Zone and when the scoreboard comes up I find out that my completely botched awful mission was a goddam S Rank.