Mr. Hattrick was somewhat of an antoganist, despite being the only one who taught Jimmy the basics of 123.
Regardless of his knowledge within either complaining or being quiet during his lessons, he did begin to harass Galloway.
But let's think of it from his POV...
Your co-worker is drinking heavily, while on the job, drunk in front of children.
You tell your boss, Dr. Crabblesnitch.
Later on, you admit him to a rehabilitation (Happy Volts) where he is supposed to get clean, but he breaks out somehow.
Sooner you make yet another attempt to get your nemesis fired, but you end up getting fired for selling answer sheets to students (which should only be punishable if he handed them out during a test or if it was mandatory to give them to students but he wouldn't unless they paid him).
Answer sheets should be able to be memorized. But since it was obviously against the school plan for Math class, it makes sense.
Oh well!