That scene at Bellatrix's vault in the movies,
That scene at Bellatrix's vault in the movies, the dragon had been conditioned to fear and anticipate getting beaten, with the jingling sound.
I found myself thinking: well,
I found myself thinking: well, there are all those times when it hears the jingling but ISN'T beaten afterwards,
(those are all the times people entered the vault after the initial conditioning) so why isn't it conditioned back to normal?
Then I noticed it must have had to do with the dragon's mental state.
"OMG I'm gonna be beaten so bad, oh god it hurt..oh..wait.. nothing happened"
"OMG I'm gonna be beaten so bad, oh god it hurt..oh..wait.. nothing happened" is an active deliberate thought-step the dragon didn't take;
rather, it just passively experienced the fear and promised pain each time for it the jingles jangled.
Then I awoke and had to rewind half the movie or so..
There's a useful metaphor here somewhere for us :)