Sorry for the double post, but: I think the ending actually shows that Finn still is not (ready to think)ing about others. Though this instance was an accident, Finn didn't think about how his tower would hurt anyone; it hurt Bubblegum, the entire candy kingdom, and a lot beyond it.
The effect is different because you…

I felt as though it was disturbing when you pointed it out, but, I think in this instance Finn may get a pass on this one. Not saying that violence is okay, especially when dealing with romance, but, he punched who he thought was Martin. She took off the disguise afterwards.
My opinion's that he probably regretted the…