To follow up on part of Qavion's post:
I've pointed out apparent minor problems to the cabin crew three times in the last 20 years, and they always took it very well. (Big oil leak on a 737, crack in a fiberglass fairing that grew noticably during flight, and a quarter-turn on a SAAB 340 nacelle that popped out on takeoff.)
Of course, I don't know if they actually fixed anything afterwards....