Support is my secondary role and I actually think it is more frustrating than laning. At least when I lose lane, I know how and why I lost. But when I play support and I play very well, it can still result in a loss. Usually it is a collection/accumulation of minor mistakes either by my teammates or myself. However, many times I play an objectively good game but can't carry from the position, I can only put teammates in position to secure objectives and kills, I can't kill people or take objectives myself.
Essentially, you can put your team in a position to conclusively win and you can still lose. There is only so much you can do when playing support to help the team win, but if they miss prioritize targets, begin a bad engage, try to pick a fight when you are down 2 teammate, or don't put ANY vision on the map at all, you feel pretty helpless.
The role is pretty thankless as well in lower elo. Supports/junglers often get blamed when things go wrong in a fight or the outcome is a loss. In ranked games I don't play with quite as many ADCs that are assholes, but in normals it happens A LOT.
Recently, I played a game where I got an S or S- on
in a ranked game. At the end of the game I was blamed for the loss and I was pretty ticked off. I missed my ult on a
which resulted in our ADC dying. But prior to my mistake and that specific instance, it was very obvious throughout the game that my teammates were not taking towers on the map. They had a kill lead and a gold lead and they were not taking towers. No one on our team besides the ADC and myself were prioritizing the objectives on the map. My other three teammates were prioritizing kills. We lost a very late-game team fight and the opposing team pushed down mid and ended. We had a pretty larger gold lead.
So I played probably my best Leona game to date in ranked and it resulted in a loss. And the loss was not due to my team feeding or doing anything ridiculous, it was just they didn't take towers. Mechanically, they were all pretty good players.