So... why exactly did they feel compelled to tear their shirts?
There's a scene in Laputa: Castle in the Sky (the Ghibli film they're watching) where the beefiest of the henchmen chasing the main characters gets into a manly-off with the foreman of the mining town. They end up flexing until their shirts pop off, whereupon the foreman's wife asks him who he thinks is going to mend the shirt he just ruined (Ai's mom's quote in this page).
There's a scene in Laputa: Castle in the Sky (the Ghibli film they're watching) where the beefiest of the henchmen chasing the main characters gets into a manly-off with the foreman of the mining town. They end up flexing until their shirts pop off, whereupon the foreman's wife asks him who he thinks is going to mend the shirt he just ruined (Ai's mom's quote in this page).