Mike can't read between the lines.

As you know, one of the less palatable of Middle Years Mike's traits is his being too blasted stupid and into himself to realize when he's putting Martha on the spot. He hadn't the vaguest idea of why Martha had to share his note because he didn't want to admit that she was just as much at pains to fit in with the girls as he was with the guys and he hadn't the blindest idea (nor especially wanted to have said blindest idea) that the reason she didn't write him is that most people aren't good at writing letters and have a hard time trying to decide what to say. In both instances, Mike reminded us that he's an extension of a woman who isn't very good at understanding why people do what they do and also tends to be a gloomy idiot who holds grudges and has impossible standards to meet by acting like he was this huge hero for exhibiting the bare minimum of common decency.

This, I should think, is because unlike his creator, Mike had in his arsenal the wonderful thing called "a friend who can call him on his weak BS and make him listen." Good old Gordon was in his corner telling him to not act like a swinish git and make up with the person who didn't actually snub the fool. Personally, I wouldn't have stuck my nose in and let the fool get embarrassed when the truth finally hit him over his stupid head but I'm not a nice person by any stretch of the imagination. His incessant and idiotic wailing about being a bug on a windshield the second things don't go his way offends me and I wish to see it punished, not rewarded as it is here.