As I have said many times on these forums, at some point in the training, perhaps at upgrade to sfo, all pilots should do a two-week gliding course. Gliding is unique, in that it is all seat of the pants hand flying, in the most challenging conditions. In a strong bouncy thermal you might incipient stall the glider ten times while banking at 45 degrees - it is normal, and the reaction becomes normal. Positive and negative g are a central part of bouncy thermal flying. And of course all the training aircraft are certified for full aerobatics. If you are a (young) commercial pilot who has never flown a glider, I can assure you that you will come out of the course having learned many things about aircraft about aviation, and more importantly, about yourself.
I fully concur!
I believe the U.S.A.F Academy cadets start out in sailplanes.
It certainly gave the GAF pilots an advantage in the early stages of WWII.