While this story is pretty cute and I'm mostly enjoying it, I do have one criticism here.
In real life, catharsis does not work. I can't stress this enough, but "venting stress," like this is not a useful stress management technique. It can actually cause anger management issues in the long run.
The "Hydraulic Model of Emotion," which was popularized by Freud, but promoted as early as Aristotle's "Poetics," has as much to do with real psychology as "Humoural Theory," has to do with physical sickness. (Keeping the humors in balance was also a relic of Aristotle's time period.)
If his goal is to make her an angrier person, then his method has a decent chance of being successful. But everything he says about bottling up emotions and venting them is basically pseudoscience nonsense.