Panel 1: It would appear that as always, Mike would prefer to sulk than to get things done. This is why we find Liz asking him what's up with him because he's been lying on his bed moaning in self-pity or something. He hints at the mental infirmity that lands him into shtook next week when he says that he wants out of here! He wants to do what he wants when he feels like it!
So do most people. What Mike doesn't ever want to admit is that no one really gets to do that. Someone with his in-built self-loathing and secret belief that the world should crush him and he does deserve to be kicked in the face and laughed at for wanting to be happy gets in the way of seeing himself as having anything in common with all the people he sees as trying to destroy him.
Panel 2: He wants to be older, you see. He wonders why it takes so long for things to change because nothing happens fast enough.
He won't be saying that in three months' time. What he will be saying is "How could you do this to me?" and "I hope I don't have to share things because that means that I don't count."
Panel 3: Liz says something that confuses him when she says that sometimes, things happen too fast. Since he can never understand other people's problems, he asks her what she means.
Panel 4: She then invokes a problem that can never be real to him when she says that last week, she was just "Elizabeth" and now, she's the kid with the glasses. Since this is a fake problem to him because it's not happening to him, he looks at her with a stunned look on his stupid face.
The part of me that remembers ahead to the mad wall would gladly tell her that trying to get him to see this is pointless because he cannot admit that pain he cannot feel is real.
Summary: This belief that he's being singled out for persecution while everyone else is having a wonderful time at his expense might explain next week's antics but, man alive, it doesn't excuse his pointless and excessive rage and refusal to avoid trouble.