Your 3 highest Mastery Champions read the Boards.
How do they react to the posts about them? Balance posts (assume they can read OP.GG too and see their stats), rage posts, fan art, fan fictions, comics, jokes, roleplays, lore discussions, etc.
For example, Yasuo will learn of his controversial existence and numerous posts on how to change him, Mordekaiser will learn of his dedicated followers and his many bugs, Urgot will learn that some people want him to become a Star Guardian, and Veigar will learn about the short jokes.
######And unfortunately for his mental sanity, Lee Sin doesn't get a free pass. We have pretty good dictation software nowadays. I'm not so sure about how Rek'Sai will read. Maybe she gets some other literate void creature to read the Boards to her.
Be creative and have fun!
"The cycle of ragers on the boards continues. I will Q, they will QQ."
ummm, I really don't think he would care, at all.
She would laugh at people who complain about her being OP, say they are not in motion, and proceed to rip their souls out to teach them to be strong and fight.
"Why can't I find anything about myself?"
"Check the Ezreal threads..."
"I have been to the depths and yet have never seen so much salt before."
"If a scream of pain is a beautiful note, the cries of 10 a rhythm, and a thousand screams of agony a song then I have discovered the ultimate symphony."
Hmm. So they intend to return me to glory via reworking my kit. Turns to someone off screen. Nasus! Make sure the ones who make posts about my oppressiveness are executed. They will see what true oppression is. Leans in on screen. And bring me this "Melledonus." He thinks he can mock me and my alcohol intake without consequence?
So the boards complain that I burn things? Chuckles. It's almost like they don't know what I am. I am not equal to the other champions. I am a force of nature. I will stay in their bot lane. I will create a cataclysm the world has never seen before. My enemies will be the kindling to spark this wildfire.
Big smile as she opens her laptop. Ooh, this will be so exciting! I'll get to see what people think of me! I really hope I brightened their days! Reads balance posts that qq about her, smile fades a little. But... I have very defined weaknesses. It should be simple to defeat me in battle if they applied the correct tactics. Reads funny memes about her lazers. Laughs as smile returns to normal. That's just brilliant! Garen groans off-screen. Aw come on Garen! It was funny! Smiles fades as she reads more negative posts, this one about her getting skins and a VO update. Oh. B-but I had a pretty basic VO. They were giving me a skin so they just went an extra step... Reads more QQ posts about her balance, calling her brainless and no skill. Smile disappears. Silently moves on. Sees final post on her voice and closes her laptop. Walks away fighting back tears.
growls
Sighs and then grumbles about cowards who think he needs to be nerfed.
TACOS.
- "Who is this impostor people have been talking about?"
All of this suffering would cease in death's eternal embrace!
I see you got a problem with Lee Sin boy, maybe we could make a deal... a nerf for a meal?
Foolish mortals, these petty concerns mean nothing next to the threat that the mist poses to us all.
: ... everything about me is bananas... wtf.
: hahahahaha :3
see's Gnar hate thread
mega 
: ... everything about me is nsfw... wtf.
: Turns on laptop and drinks sake.
Time to read the boards.
: Meditates in front of PC
Ah, it's a good day to use my PC right now. Let's see what's on that's about me.
: Turns on laptop and listens to Monstercat (cuz why the hell not)
Finally, a break from exploring and the rift. Now let's see what's on the board that's about me.
last post about me is actually that old?
who dare say I'm broken? i will make them into cupcake.
...
is throwing a tantrum because of 7.8 & 7.9.
"Ooh! Look at all these pics of me!" [slayer-jinx-catface] [slayer-jinx-unamused] [slayer-jinx-wink]
"It says the website has cookies. What flavor are they exactly and how do they come out of this machine?"
sees threads about unviability in higher elos
remembers how he wasn't designed for higher elos
rolls eyes at league community
sees threads about how he should be less oppressive
reads threads, realizes how little people know how to utilize him
shakes head at lower elo community
/ 
(Kat/Akali are about equal points-wise, you can choose either or both)
: "Why... why do you ship me with Diana? The only time some ever posts about me is when they ship me with Diana. I don't even like her."
: "THIS IS AAMAAAZIIIIINNG!!!"
After scrolling down for awhile, finally finds one post. "Underpowered.... Well, I suppose it's for the best, since I'm still learning to control my powers. I don't want to hurt anyone." Yasuo walks over. "Oh, Yasuo! Come see this! I found a webpage called the bo--" 
THIS NUMBER IS UNACCEPTABLE!! (Read this in that lemon guy from Adventure Time's voice and it's much funnier.)
4: 
I don't think she'd care much. (She's not seeing a lot of threads, so the fact she's still decent would be hidden to her.)
"Now I know how to make my fears even stronger!"
Also someone who wouldn't care much. (And would probably have no idea how people feel about her.)
- hah, they are all fools
: Shenpai is noticing you, Melledoneus.
What the hell? ults computer into the wall
They think im weak hm? ults gameplay boards feed me your tears!
Oh look, it's Yasuo and Lee.
Oh look, people who can't read ability descriptions.
: "They want nerfs? Well...change...is goooooood :)"
: Rek'Sai Screeches
The bastards keep calling me weak. I'll show them.
...what is 'parkour?' It sounds Demacian, and I dislike it.
Shuts down computer, leaves league of legends
If they can't see me, they can't write about me
I don't have anything on here
: ""Their heartbeats quicken. (Because they're mad)"
: "Better nerf Irelia."
: "The only thing "broken" about me is my blade. "
, reading patch notes for the 17th time
: "YES FEED ME ALL OF YOUR DELI-uh, yeah...I mean I just a chippy scout..
: FOOLS, they don't know true balance