i'm not afraid anymore

The fact that Will got to see Mike react, positively and lovingly, to HIS feelings. To the love HE has for Mike, and how having Mike around makes HIM feel. He got to see visually what Mike would look like if he reciprocated, but only because he let Mike believe those feelings where El's.

It used to be a silly game, saying dirty words to make the other laugh, but there’s nothing funny about it now, and Mike isn’t sure when they stopped laughing about it.

does mike wheeler know that being his happy self makes him gorgeous

I stand by this. Will doesn’t know how to apologize because he never does anything wrong. On the off chance that he does, he just walks up to Mike and gives him the saddest little puppy dog eyes. And he’s forgiven.

It used to be a silly game, saying dirty words to make the other laugh, but there’s nothing funny about it now, and Mike isn’t sure when they stopped laughing about it.

I headcanon that when Mike and Will were little and played pretend, Mike got on one knee as if he was a real paladin. He would have held Will's hand, they made up an oath together and doing the events of season 1 and 2 Mike constantly reminded himself of the oath.