The whole "don't attack the tanks!" mentality is frustrating, believe it or not, for supports. Instead of trying to support my team who is a reasonable distance from the enemy, staying out range of their carries the best they can, I have to deal with them taking a ton more damage, and putting me in much greater risk. I can support the fuck out of a team that takes reasonable risks. But when Sion charges STRAIGHT THE FUCK IN to kill their carry, I can't heal that, I can't armor you up, Lulu's E and ult aren't going to do shit to protect you, Sona's R, if I get close enough to get it off without melting aren't really going to save you for very long. Then he starts yelling at others to do the same, and unfortunately they listen to him rather than me, so my whole team is running into the Machine of Death that is the Irelia he fed during laning. Rather than laughing about how we have Malzahar and Ashe and their only range is an underfed Annie.
Actually, I think I'm starting to learn that a bad AD partner is one of the less frustrating things as a support. It changes if they're bad and blame me for not somehow saving them when they dive, but a just plain bad AD isn't that hard to cope with.
The worst, Gee Willikers THE WORST, is in pregame chat when someone calls support before I do (or insists on it after I call), and then they don't buy any wards. This makes me want to murder. It makes me wish "not buying wards" was a reportable offense. I would vote punish on any tribunal case with a report like that.
Second worst is the aforementioned bad ADs that blame me. Then the people who rush in. Even worse when they blame me/others. "Soraka why didn't you heal me?!?!" I did, but the damage you took far outweighed my W, and my R, and my summoner heal.
Mids and jungles that don't ward is somewhat frustrating too. Ward the other side of my damn river, please. Ward up our jungle. Ward up their jungle!
People who initiate on baron without fucking sweeping wards. I sometimes hope hell is real, and God is a support player, because if so there's a level of hell for people who don't put a pink down before killing Baron.
People who chase into bushes, and people who initiate fights near bushes. Look, sure the three of you can kill that Vayne easy, but you can't kill the four of them in the bush that she's baiting you towards.
Basically, everything is frustrating on support, because you can't do shit without others. Supports tend to have crappy escapes, so I can't even push a lane away from our turrets alone. So if my team decides to attempt baron when they're all healthier than we are, I have to go along and help them, getting aced, rather than split pushing during the team battle or something that can at least offset the horrible loss I see coming.
Most frustrating is people who flame though. Look, if someone's doing bad, whatever. I'll be the first to say to my AD something like "please stop initiating so hard, they can win straight up fights, let's farm". But there's no reason to insult them, 99% of the time they're earnestly trying, and well-meant advice will help you win far more than "Gee Willikers this ad is feeding". Even if it's too late, they're just not good enough, you've helped them! They'll be better for the next game. 1% of the time, they don't give a fuck, they're doing it their way, effectiveness and advice be damned. Flaming them isn't going to help either. And honestly? I don't know my Elo, but it's probably on the low side, so if you're in a game with me, you're no Salce, so you have a lot you could do to improve your own play.
avatar from Nononono by Lynn Okamoto.