Engine outs
I had an instructor who reached out and actually switched the engine off in a 152 at 3000 feet; albeit over a low flying area, and with plenty of warning.
His reasoning was, he wanted me to feel how scary and quiet it was if it ever happened for real.
Very sobering experience.
The same guy had me do a dead stick grass landing beside the runway.
Really puts the pressure on and makes you realise if it happens for real, you'll go down real fast, and you only have one shot...