I love this scene. It's from About a Boy, a film I was initially pretty lukewarm about. I found Toni Collette and Nicholas Hoult to be too strange looking and Hugh Grant was too cloying. (Yes, I know this was the point, but it was much like my hatred of Frank Burns on MASH when I was a kid. You're supposed to hate him, but my hate for him made it impossible to see beyond it.)
When I saw the film again a few years later I found it quite charming. I was able to overlook what I'd found vexing before and see how right the film makers had gotten it. I love how the jaded Will somehow lets himself fall prey to a misfit kid. I love how the suicidal mother that is supposed to be so self-aware and determined to take on the world is oblivious to the way that same world actually works. And of course, what is there not to love about a clueless lost boy being the one to make the maladjusted fit for public consumption?
This scene is one where characters sacrifice the need to look cool. They throw it out the window because it will please someone else. It's masochistic, really. Such an act would've been devastating for a kid like Marcus that was already a social pariah. For Will, such an act could've made his mind explode with self revelation. Because of the magic of movies, however, it all turns out just fine. Marcus is not the biggest freak on the stage, so he wins a few points with the loser boys in the audience. Will's willingness to drop all pretense makes his dream girl realize he's not such a shallow lost cause after all. The mother in the Yeti jacket is left pretty much unchanged, but even cinematic efficacy can't win them all.