Dude Twitch "mains" are just people looking to abuse whatever´s OP.
Try talking to the real long time ADC mains, they are the most patient, chill and usually quiet people you´ll ever find in a team.
They would be the people who played Ashe,kalista,cait, lucian and who else under the lethality meta.
After the mage update, during the tank patch.
I myself am only a semi main, i often rotate around due to having champs i like in all the roles but i do main
and
since about 1 or 2 seasons back.
Before the static shiv buffs you needed a good deal of patience to succeed on Trist x)
You have and will always need it on ashe, she always get's screwed sideways for the smallest of mistakes.
MF is probably the most forgiving due to her movespeed, and since i didn't start playing her until i reached gold i already had a fairly good sense of when to ulti which made the champ quite strong.
But she is also terrible if you fall behind in lane,thus being careful and avoiding mistakes was a must. x)
Currently she is kinda forgiving, duskblade and all that, but most champs have had time periods when they have such strengths.
Marksmen are the role commonly expected to have the most farm, to die the least, to position the most perfectly, to deal the most damage,to kill enemy tanks and squishes alike, and to also take the first tower.
That's a lot of expectations on the head of 2 people x)
And i write two because i usually end up being carried by my own support since the lane is a hundred times easier when the support is good at their champ, when the two people are on the same page and act together there hardly is any better feeling.
Except the Pentakill feeling, that's a a pretty great one.