Choices. What are the Perks of Always Doing The Right Thing?

Do the right thing, do the right thing
Do it all the time, do it all the time
Make yourself right, never mind 'em
Don't you know you're not the only one suffering

Often times, we are provided with two choices. To do the right thing (the best thing for the greater good) or to do the opposite (selfish acts, in spite of others while damming the consequences)

Believe me; by saying that. I don't think the world is black and white when infact most of the time, what we are confronted with is mostly all grey or black, or grey or white, or different shades of grey.

In such scenarios, how do we manage to keep to a strict moral code of only doing the right thing?
I dont know the answer to this. And that troubles me.

Using the concept of opportunity cost from economics, we could try and reduce the the collateral damage from two choices, however choosing the lesser of two evils never actually amounts to doing a good thing.

Or could I be wrong? Am I just being a goody two shoes? Life seems to go on easier for those who pursue what they want and damn the consequences it might have on themselves or others.

Narcissists actually do find it easier to get stuff done and move ahead faster in life.

So what exactly could be the perk of being a perfect wallflower? With an unbridled desire to always do things the right thing or do nothing atall?