Panel 1: On the drive home, we find Liz riding shotgun as Mike tunes the radio to the rock station Elly hates. This is he can listen to "I Gotta Shout" by The Emetix. The singer has a stabbing in his gut, he don't know whut to do because his baby gone and shut him out. Hmmmm. I wonder if the singer is so oblivious, he can't remember her name half the time.
Panel 2: He then he says she gonna try with another guy, he never thought she would dump him and he don't know whut it's all about. I wonder if she told the moron only for him to not connect his being a shitty boyfriend with her getting sick of crap like note protocols or inability to understand what making a boy jealous looks like.
Panel 3: His response to his self-induced trauma is to shout in incoherent rage.
Panel 4: Mike loves sentimental songs like this.
Summary: This is because he's the sort of nincompoop who can't connect what he does to how people react to it. He also studiously avoids admitting to being the problem....as Liz can surely attest.