Something that grabbed my attention in Season 4 is that Mike and Will kept talking about the past year. Will says, "It's been a year, Mike." Mike says, "The truth is, the last year has been weird."
But it hasn't been a year since Will left! It's only been six months.
Season 3: June '85. Will moves away in September '85.
Season 4: March '86. 6 months after Will moved in September '85.
They're not only talking about the time since Will moved away. They're also talking about everything that happened in Season 3, and even a few months before that!
And... we all know what happened in Season 3. It's the reason for the rain fight: Will was constantly left behind by Mike in particular, always the third wheel, always in the background – meanwhile, Mike and El were attached at the hip (sometimes literally) and separated themselves from the rest of the Party. Before their breakup, at least.
Will says the two had "been like this all Summer". Summer break in America lasts 2-3 months, usually starting in May/June.
Mike could probably balance Will and El a little easier when he was still in school, because Mike had to be there, Will was there every day, and Eleven wasn't there at all. But when Summer break started, it became way more noticeable just how much time Mike and El were spending together. It lines up perfectly.
That's why "the last year has been weird" for Mike and Will.
So, what does this prove?
Well, it means that Mike and Will's problems didn't just start because they accidentally lost touch after the move. The problems started before then – ever since Mike and El started spending all their time together in the Summer of ‘85.
“I feel like I was too worried about El, and… I dunno, maybe I feel like I lost you or something.”
;)
