'nother "teacher" story here.

Little background knowledge: I'm repeating the things he told us about at home and try to learn them by myself. I use the newest Visual studio and .NET framework version.
In school we have pretty old PC's and even older .NET framework. But let this insanity begin...

As normally i entered my classroom a little late (I have a dangerous habit of ignoring my alarms) and sat down on my chair. We were only 3 people including me at that moment so everything was pretty chill. I ask him what our task was and something along these lines occurred:
Me: what's our task?
Teacher: you remember your shopping list program? I want a textbox in it next to the listview and I want it to show every listview item
Me: that doesn't make sense
Teacher: yadda yadda just do it
Me: kaaaaay, anything else?
Teacher: actually yes! Please use inheritance.
Me: *baffeld* that doesn't make any sense at all. We have 5 different fruits; you tell me i should make a class per fruit!?
Teacher: yes of course! This is how professionals do it all the time. Please give them a distinct attribute, too.
Me: *angry* I'm. Not. Gonna. Do. This. This is total bullshit and also really bad coding style. I'm not going to teach myself something that doesn't make sense at all.
(Note: i know how inheritance works and he knows that too)
Teacher: You have to do it, you won't be prepared for final exams otherwise!
Me: leave my exam prep to me. I won't do this.
Teacher: *grumbles* fine

Later that very same lesson i got a .NET compatibility error. I couldn't work because I wasn't allowed to change anything on the installation nor to install a newer framework. So basically he told me I should've used 'sharpdevelopment' (which is not able to do windows Forms, but hey who cares) and this would not have happened. I was so furious at that moment i just took all my stuff, told him that I work 'from a place where i got decent software and space to think' and left the room.

Why did this person decide to become a programming teacher?