One of the worst parts of playing support isn't only that it's "unappreciated", but also that you're almost always the first one to get shit on when people get salty that they lost the game.
I've had someone get mad at me for playing Lucio because, in their opinion, I wasn't healing them and instead kept the speedboost. Except I wasn't, I would always change to heal as soon as I got to the point. He was salty that he was "being shat on", even though I had to point out that a Lucio's passive and even active healing doesn't cancel out multiple characters shitting on him, so he can't just blindly charge against 3 different people at the same time. Guy couldn't understand that Lucio doesn't bail out someone who is playing shitty and just charging to the enemy frontlines with no plan or other people backing him up.
Also had people all hot and bothered when I'm playing as a Mercy, where they expect instant healing regardless of their position in the map to make up for them playing sloppily and taking too much damage, do nothing to protect me, then whine I don't pop and ult when everyone dies because I died along with them. Way too many "lone wolf" players who aren't tanks who go way out away from the frontlines also expect constant healing. Nope, sorry bud. I'm not charging behind enemy lines behind you with no plan on your end, where you're gonna get your ass killed instantly and I'll be left on my own to get killed as well, when I could very well just be in the frontlines healing 3-4 teammates at once.
I don't pretend to be the very best Lucio/Mercy player, but people are just waaaay too eager to shit on people who play those two characters instead of realizing that they a Mercy/Lucio doesn't make up for their shitty playing/bad team coordination.