Is it wrong to sit back and allow someone to make their own mistakes?

On one hand, it’s really none of my business to interfere with the decisions of others. If I keep a ‘mind your own business’ mentality, I believe that others would find this more socially acceptable. Although I have my strong opinions, perhaps it’s better for others to learn the hard way. Even after I have given my advice on countless occasion, someone still remains oblivious and continues down a losing road. Is it right to just sit back and watch this happen?

On the other hand, would it make me a bad person to do nothing? Is this moral? What would you do, really. I find myself a villain no matter what the choice.