The BGA instructor's "how to damage yourself spinning" scenario goes:-
a) You're a bit low in the circuit
b) Instead of modifying the circuit you continue to fly your "normal" pattern but subconsciously keep the nose a bit high (= speed decay without a noisy lump on the front of the aircraft)
c) You're now low on the final turn and start worrying about wingtip meeting trees or whatever, so you keep the bank shallow
d) But now you're not getting round the final turn quickly enough so you feed in more rudder
Then insert your final words "Oh f..." as the world rotates
PS The above is only demonstrated at a very safe height. But especially in a Puchacz it certainly gets the pupil's attention!
Ergo: - It ain't steep turns on finals that get you, it's the slow shallow ones!