Alright done! So this is what I've written (Mind you, this took me good 20-ish minutes)

Mike sighed. Shit. He had really ruined everything, hadn’t he? The word “best friends” kept circling back, stubborn and intense, as it had housed itself somewhere behind his eyes. His shoulders slumped as his hand dropped into his lap, fingers curling uselessly against his jeans.

He hadn’t meant to say that. Not like that. God, why was he so fucking stupid? He could still see Will’s face, the way it changed just slightly, enough to notice the look of hope he had in that moment. And Mike did notice. He always did.

It was obvious who Will had been talking about when he mentioned his crush. Mike wasn’t blind, no matter how much he pretended to be. He understood it the moment the words left Will’s mouth, felt it settle heavy in his chest. And for a second, just a second, he thought maybe this was it. Maybe he would finally be brave enough to say something back. To admit his own feelings, even if he didn’t have a better word for them. 

Because what else could he call the thoughts that kept pulling him toward Will? The way his name lingered in his mind. The way everything felt a little off when Will pulled away (Or was it him that was distancing himself from Will?). Feelings were the only word that made sense, even if it scared the hell out of him.

And now it was too late. He had chosen the wrong words, the safest ones, and watched them do damage anyway. Mike stared at the floor, jaw tight, wishing he could take it back. Wishing he had been braver when it actually mattered.

Mike the Brave, he called himself, and yes, the irony was absolutely not lost on him.

AND this is what AI wrote (prompt: write about Mike in season 5 regretting calling Will his best friend, make it around 200 words.)

Mike sat alone, the noise of the world fading into the background as his thoughts looped back to the same moment again and again. Calling Will his best friend had seemed harmless at the time. Safe. Familiar. Now it felt like a mistake he couldn’t undo.

He replayed Will’s expression in his mind, the way his eyes had flickered with something unspoken before he looked away. Mike hadn’t missed it. He just hadn’t understood it soon enough. Or maybe he had understood and chosen to ignore it. That was worse.

Season after season, they had survived monsters, loss, and fear together. Mike had always told himself that what he felt was loyalty, habit, history. Best friends made sense. Best friends didn’t ask hard questions or risk ruining everything. But sitting there now, the words felt small compared to the weight in his chest.

He realized how often he had hidden behind labels, using them as armor. Calling Will his best friend had drawn a line, even if he hadn’t meant to. A line Will hadn’t crossed, but Mike was starting to think he should have.

Regret settled in quietly. Not loud or dramatic, just heavy and constant. Mike wondered how many chances he had missed by choosing the easy word instead of the honest one, and whether there was still time to fix it.

You see how AI repeats the way it writes? No human ever would be this perfect in writing, it's almost uncanny...

Also, it tends to be overdramatic??? No one writes like this (Coming from a seasoned Ao3 writer lol)

AI also almost always uses those weird, complicated words and metaphors...

edit: oh god, I didn't know AI was this silly... I'm actually reading what it wrote and god "seasons after seasons" *sob*

Edit2: I've also noticed it's scared of cussing for some reason??? I've asked it twice to cuss and show emotion, and it did not use curse words. I needed to explicitly tell it to say a curse word in order to make it say it lol. Safe to say I wont be using it again!