Slow flight
Can't believe it has been 40 years since I got my ticket.
My instructor was a crop duster, and very thorough. He taught me slow flight, stalls, spins, accelerated stalls, approach stalls and many times, recovery [under the hood] from unusual attitude. Yes, he cut the engine on me - more than once - and a few other things I won't go into on a forum. I feel it made me more aware of the consequences of an engine failure, and more alert for even small issues. He taught me to feel the airplane, not to just work the controls.
BTW, I really enjoy spins...still enjoy snap rolls, too. Tom was an excellent instructor. Created a good friendship, as well. Amazing how trust will do that.