Nothing more than to reiterate this.
I've have learned to dull my senses a bit.
If it vibrates a little weird, I wait for the vibration to come back. (It never does). Or a clunk here or there (usually a ham fisted pilot playing with the trim).
Spidy sense and the hair on the back of my neck are always up.
I've said it many times before, and I'll keep saying it again with my diatribe here:
Unlike airplanes, helicopters simply have a death wish, wanting to commit suicide at all times, and waiting for the right moment when the pilot isn't paying attention, so they can take you with them. It's nothing personal.......for they do warn you beforehand: The helicopter does in fact talk to you at all times. But woe be the pilot who 1. Doesn't listen to what the helicopter is telling him (complacency), or 2. Doesn't fully understand the language the helicopter is speaking (inexperience); for the helicopter will interpert both of these failures to listen to it, as a pilot who
also has a suicidal death wish same as the helicopter, and who
gladly wants to share with the helicopter a double-suicide fate. A fate the helicopter is more than happy to accomodate. And the helicopter is, and has always been, equal opportunity in this regard; for it harbors no hatred, holds no personal grudges, and does not discriminate in any way, shape, or form.
Helicopters have no friends, don't want any friends, and don't care to be your friend. Understand that, and you will be fine as the pilot of them.