These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
"That's Your Funeral" if you don't think that's an ear worm.
"Food Glorious Food"
"Oliver, never before has a boy wanted more."
"You've Got to Pick a Pocket or Two"
"Reviewing the Situation" to a lesser extent.
"Consider Yourself One of Us"
"Oom pah pah" that's how it goes
"Who Will Buy?"
Most songs apart the more depressing ones such as "Where is love?" and "As long as he need me".
Moral Event Horizon: Sikes crosses this when he murders Nancy. You know you have done something utterly unforgivable when your dog, an animal which is famous for it's Undying Loyalty, turns against you.
Nightmare Fuel: Nancy being beaten to death by Sikes while Oliver is Forced to Watch. Also the fact that she was still twitching is very hard to watch.