This is a Michael "Mike" Wheeler rant post. If you like Michael "Mike" Wheeler this maybe isn't for you.
First, something that was thankfully addressed by the narrative: during the entire run of s2 and s3 Mike was controlling of El. He, unintentionally at first, but then entirely consciously in s3, exploited her lack of social skills to make her completely dependent on him for social interaction. And then when she breaks out of the cycle he gets mad and acts like a dick toward not only her but Max as well (a repeat of s2 where he was being rude to Max for daring to be a woman who entered the vicinity of his friend group). As a direct reaction to that situation, he calls women a "species" and him and Lucas just go into the whole "we can't possibly understand girls" talk. The whole thing is just...blatantly misogynistic but as I said, it does get addressed by the narrative. (Even though that arc is ended by him asking El "does your species like chocolate" in an M&M's product placement scene .💀)
How in s1 when El defends him from his bullies, he fully applauds and welcomes it but when she defends herself in s4 he screams "what did you do?". And I've seen some people claim that "El lied that her and Angela are friends so he didn't know" my brother in christ he was THERE he SAW what happened. El being violent and protective is only okay when it serves his needs, but not when she has to defend herself.
And then there's Mike's treatment of Will. Now, I will approach this from the "Mike is bi/gay" point of interpretation, which might explain that he's projecting his insecurities, but doesn't excuse any of his actions.
In s3, he repeatedly made Will feel stupid for wanting to be around his friends. He makes him feel like a child for still being into DnD. He makes him feel like he's being clingy for wanting his friends to be around (even though he literally just went through the 2 most traumatising years of his life). He explicitly puts that guilt on him when they fight in the garage. I'm gonna get to the line "it's not my fault you don't like girls" in a second.
In s4, when Will asks why Mike is talking to El but ignoring him, Mike responds with "because she's my girlfriend, Will." Now, pointing out the obvious. He's been ignoring Will for a year. He also forgot his birthday. A person he supposedly cares about, he is completely neglecting. Which like, whatever the reason, dick move. And second, Mike is insecure about his own relationship and "heterosexuality" and taking it out on Will by making Will feel guilty. The line implies that Will is asking Mike to treat him like his significant other by LITERALLY JUST ASKING HIM TO NOT IGNORE HIM. He is using Will's sexuality, which he KNOWS is something Will is insecure about, to hurt him. He is implying that Will is somehow crossing a boundary and acting weird for simply wanting his "best friend" to talk to him. This is not even the first time he does it, because, in the garage scene, he also implies that Will is somehow placing the blame for his loneliness on Mike, and Mike says it because he KNOWS it'll hit him where it hurts. Similarly, he calls Eleven a monster because he knows that's what she's insecure about.
He is so self-centred and lashes out at people when they don't go according to his plan. He knows what makes his friends tick, and he uses it against them. In s2, he narratively went through the arc of learning he is not the main character. Throughout that whole season, he grapples with not being the centre of attention anymore. The fight he has with Lucas over who is going to be Peter Venkman is symbolic of that. Mike is mad that Lucas thinks he can overshadow Mike and be the main character (speaking of that scene makes Mike look racist as hell). That arc was good, except it didn't wrap up in s2. It feels like this arc just kept going and going and they just tuned Mike into a whinny and unhelpful bastard. It feels like he still hasn't learned he's not the centre of attention, and he still views the people around him as sidekicks.
Also, I dislike him for less constructive reasons, such as he's just generally and unexplainably annoying.
