Entertaining myself with the concept of Mike and Louis being friends, but only outside of work. While inside the building they actively hate each other, but have scheduled lunches/hangouts where they get on like a house on fire
Louis will be mid sabotage effort when he just stops glaring and asks, "Oh by the way, are we still on for brunch this Saturday?" and then Mike will also pause and give a very cheery "Oh yeah, definitely. You pick this time," before immediately dropping back into a sneer and taking files from him
Everyone is very confused by the seemingly random switches, and when pressed about it both parties just say that they're friends outside of work. Immediate cut back to the two of them glaring at each other across the office and making threats on their lives
The person most perturbed by all of this is, of course, Harvey. He doesn't even pick up on the fact that the two hang out until months in when he just so happens to overhear them talking about something related to a hangout
He is immediately overcome with a BURNING anger thinking that perhaps Mike is betraying him for Louis of all people. He sort of stews in it for a while slowly getting more and more agitated, snapping at Mike more because of it before Louis finally pulls him aside one day
Turns out Mike talks about Harvey a lot during these hangouts, but not in the way that Harvey was thinking with betrayal and subterfuge. Instead it turns out Mike really looks up to Harvey, and has quite the crush on him. Not that Louis explicitly said that, but he sure did imply
Louis basically tells him to get his head out of his ass because he hurt his friend's feelings by being mean to him for weeks on end over some stupid assumption instead of talking to him like a grown up
Harvey tries pressing by saying that Louis is using this "friendship" to try and sabotage Harvey or turn Mike against him and Louis just looks at him like he's stupid. He's like, "That kid would rather kill everyone in this building and then himself before even THINKING of doing anything even slightly harmful to you"
Cue Mike walking in and Louis straight up asking him if he would rather work for him instead of Harvey and Mike gets the most DISGUSTED OFFENDED face ever before physically recoiling and saying "Never in a million years. You suck"
Then Marvey kiss and live happily ever after and get married and Harvey has to put up with Louis showing up at his and Mike's shared home for brunches and such
Bonus points if they hate each other both in and out of work so they're glaring at each other and making threats every time Mike's back is to them