Before going tot he champion specifically, I just wanna point otu a few things. First, I am not a person that regularly has trouble against Yasuo. in fact, not only do i never ban him, i welcome them to dare face me in lane so i can catch some freelo. I do not fear Yasuo's nor do i have trouble laning against them. TBH, I find 
way more obnoxious to deal with. Second, I wanna say that as an aide to what contributes to it, he attacks the most obnoxious type of league player. Yasuo layers are usually the type to instalock him into every game regardless of the needs of the entire team, then whine and complain about how its the jungler or their teams fault because they don't know hoe to play the game unless they are fed.
More on the champ itself it is because he feels like daddy's favourite on the rift.
When you lane against Yasuo, it is always far more taxing on the player playing against Yauso than the Yasuo himself because of all the freebies and get out of jail free cards he gets.
in the midlane, if playing against an assassin as a mage, you at least have the caveat of your ranged advantage to abuse, while still being careful of the AD assassins threat zone.
In the case of 
, He has Mana, so he can't reliably harass you but you can reliably zone and harass him. His only harass tool is W and as long as he doesn't land both hits, you are safe. if he does, just back off for a bit. His W CD means you have a window to act in, and outside his Q which is 1 way in, and no way out, he has no mobility in lane. He can mitigate some of your harass by farming with Q but this will drain his mana bar, which is good for you, as it will remove his ability to pressure you since he will not be able to cast spells, else he will go oom.
has energy and spends his entire energy bar for his harass combo, which gives you a window to act in and capitalize on. His only real mobility is his W which puts him in with no way out unless he uses it defensively.
In both cases, getting 
-> 
ill petty much absolve nay lane pressure they have on you unless a jungler forces you to use it.
With 
, none of this applies. At all.
He has no properly wide window to act in since he has low CDs on his Q and E. has underrepresented and nearly ungated lane mobility with his E which is also on a low CD, gets a free shield for walking and using his E to absorb what harass you manage to get on him, and then he has Windwall to block what retaliation you have when his Flow is down.
He has good clear with his Q-3 tornados which also constitutes as harass. His E basically makes it to where you aren't even so much as allowed to stay behind your minions for safety, which is literally the first cardinal rule of league of legends, his having his tornado innately zones you off even the backline of the minion wave because even if you are decent at dodging skillshots like me and can basically always dodge his Q, he can just E-> EQ-> E and hit you with it with no way of you dodging it or retaliating since Q 3 is the hardest form of CC in the game next to Suppression.
One of the most frustrating things in the world is having your own minion wave feel like ti is betraying you, and Yasuo is the champ that feels this way. You run down the map and are 5 miles ahead going o your tower? if Yasuo is chasing you and a minion wave just happens to come by, he basically got you for free.
Walking away from tower after hitting it to go B? Whats that? A minion wave just happened to show up in a line formation for yasuo to E- E - E to you? Sucks for you m8, you are dead. Not even 
will save you.
Building -> isn't adequately effective since unlike other AD mids, he has good sustained damage and gets double Crit and % armor pen when he gets his ulti off, so you are screwed either way. You can his all in, but ti doesn't matter because he can and will just DPS you anyway, easily able to kill you in like a handful of auto attacks.
Speaking of his Double Crit and 50% armor reduction, lets talk about my most prevalent issue with Yasuo.
Going a bit on a tangent about the very idea of a champion having 2 passives, either of which would individually be great for any single champion, something i have pointed out time and time again, but my main problem with it is that even if you dumpster him in lane, he can easily shrug off the dumpster with 1 item purchase due to his sheer stat efficiency.
If I beat a Zed or Talon in lane, got my and farmed well, they basically have to play at MY mercy as opposed to the other way around, and become reliant on proper outplay and decision making on the map to compensate. Yasuo? Nah. He just comes back with 1 crit item and pretends he was winning lane the entire time.
Which is where me saying he gets too many freebies and get out of jail free cards comes from.
He has a kit that absolves him of any and all weaknesses any melee would or should have against ranged champs ON TOP of having scalings that help him stay in the game even if he does get dunked on.
To add to this, even if he is unable to get his tornado off on the right target, because I as the player properly avoided it as the main means of counter play to him, he can just have a teammate click on me with a point and click Knock up and get a free ulti on me.
Oh, whats that? Did i say Knock up, silly me. it is SUPPOSED to be knockups/suspensions, but since Riot hasn't coded the game to properly distinguish them from one another, he can actually ult off of ANY DISPLACEMENT, no matter what kind, how minor or how small!
So even if you position correctly and follow the steps to properly not get in his threat zone, he still can get handed a free click of a button way to nuke you and get on top of you.
He can be 3 screens away but because Vayne Used E on you to push you away for her own safety, and Yasuo happened to be within the area, probably doing Gromp while he watches his tam get ganked by you and pressed R, you are SoL.
Lastly, and more infamously, is that bullshit where his Ulti puts him out of tower range when he ulti's.
That BS speaks for itself. >__>
What that? You ignited him or put your DOT on him while he was at 20 HP? all he has to do is dash around like he is mental breakdown spasms and run around and his flow shield will save his ass. =-=
Did i mention Winwall hardcounters a counters the vast amount of champions kits with one spell, and he can basically become invulnerable by standing in the thing?
Again, I don't have trouble against Yasuos. I don't even think he is freelo or OP. The examples or scenarios I gave were all made up or things I have seen happen as opposed to purely things I have had happen to me, but I think these as well as a few others properly exemplify why people can't stand him.
it's kind alike that guy that played with that one BS Character in a fighting game.
They are beatable, you probs even wreck their shit in on a regular basis, but it always feels like you are playing against them with an inherent need to perform more intensely than they do, like they have crutches and handicaps in place while you don't, and that's what makes Yasuo so hated and obnoxious to play with.
And then when you play with them on your team at a tourney or something, your friend playing the character always whines when he can't faceroll people that actually know hat they are doing.
Yasuo is the kind of champ that you can;'t just stick into any old comp either. Comps typically have to be build around the motherfucker for him to e most effective. So the prevalence of people instalocking him into any game only to under perform is only that much more accentuated.
I can play against a Shaco, Zed or Talon and get dunk'd on, and all I will think is "fuck, this guy got me".
With Yasuo, all ever think is, ugh, this guy got enabled.
Yasuo is a lane bully that becomes a lategame carry. Who the hell thought that was a balanced decision?
This might sound weird but I have a nickname for every champion.
My nickname for Yasuo is Cancersuo, as uncreative as it is, because nothing is more apt to describe this abomination.
takes more skill than Yasuo LOL
.
to lane