What will People say?

First of all, let me make one thing clear. When I say "people", I'm not referring to either relatives or friends.
No. I'm referring to "public opinion". I mean, just take a moment and count the times when you do something that is considered wrong, or you have a "bad" habit, and your mother asked you "What will people say?". What she meant is that public opinion (people) would disapprove your actions or habits.
Personally I think we shouldn't care a lot about "what will people say", because they always see things from a certain point of view, and will judge you wrong.
Here's an example: A boy is walking downtown with his girlfriend, and suddenly an old man is trying to hit on her. The boy reacts, and the old man demands for a fight. Now, if they fight and the boy kicks the shit out of the old man, people will say "Oh my gosh, look at the punk! Beating up a poor old man like this! Shame on you!". If the old man wins, which is something that happens occasionally, then people will say "Hahaha, that wuss got his ass kicked by a weak old man!"
I hope you get my point.