This story arc by writer Brian Michael Bendis, penciler Mark Bagley, and inker Art Thibert, finds Peter Parker with two problems. First, he and Mary Jane have broken off their relationship, which has effectively ended their friendship as well. Second, after his battle with Venon, his costume has been ruined (at least he did not lose it this time). He has jury-rigged a mask, but the eye lens keeps falling out. Then while hanging out with all the kids one night, he sees Geldoff, a foreign exchange student who makes cars explode (by looking at them). Things start going better for Peter (he makes up with MJ and she makes half a costume for him), and then he confronts Geldoff.
What I like about this story arc is that Spider-Man and Geldoff have a big argument over whether or not Geldoff is a mutant. Spider-Man thinks it is obvious but Geldoff rejects the idea. Then the X-Men show up. Actually, it would be the female members of the X-Men. Eventually they get around to action, but the most fun in this story arc are the conversations Spidey has with Geldoff and the X-Women. Given that it is interesting that issue #45, "Guilt," consists mainly of Aunt May having a session with a psychiatrist over her feelings about Peter disappearing all the time and that horrible Spider-Man person, running around in his pajamas and doing whatever he wants.
"Irresponsible" does not really make sense to me as a title for this collection of stories. For most of these issues the key factor are the conversations that Peter, Spider-Man and Aunt May have with others. Bendis gets a large portion of the credit that normal this time around, especially because he provides a nice mix of heavy conversations and comic dialogue (Kitty Pryde has a crush on Spider-Man, the first non-mutant superhero she has ever met). Even without a big name Spider-Man villain (the Kingpin shows up for the next story arc), "Irresponsible" flesh out the "Ultimate Spider-Man" characters in some interesting and fun ways.
Another reason I liked this comic is things actually go relatively smoothly for Peter. His relationship with aunt May improves (wow!). He and M.J. are back together, and stuff. It's not all sunny-sunny, (thank you, Bendis!). I just wish there was more pow-smash stuff.