There are training aircraft that are docile, and don't bite even if you flap around a bit with the ailerons.....
And then there are the ones that kill people.
I prefer the first type of glider, and so do most gliding clubs, its called a K13.
The other one, the Puchaz, afficionados declare it does just what it says on the tin, with that monster rudder; but all the same, it bites, and the nose up a bit on a final turn is liable to be a final turn....but it is Polish, and that says it all.
A well known British pilot, riding as pax on an aerobatic fight in Poland, was hanging on for dear life while the instructor flew around mostly upside down.....