So you've run into a critical choice. You can either be or do something good, or be bad. You may want to be good, but something's tempting you to be bad. Which way should you go?
Well, one case in which this becomes trivial is if being good will lead to you receiving a reward that is exactly the same as the temptation for being bad, but better. You aren't being good because you value the rules of society or morality or anything similar: you're doing it because it's the optimal option.
The classic example of this trope is any number of morality stories in which a character finds a wallet containing money and is unsure whether to return it to the owner or not. They eventually decide to return it, and when they do they receive a financial reward greater
than the amount of money in the wallet. This becomes a Broken Aesop
because of the implication that the reason to return the wallet is nothing to do with respect for property or morality, but because it will lead to greater financial gain than taking it would. Being good doesn't mean sacrificing anything; you should do it because it's the optimal path for personal gain.
- In Bioshock, the temptation to harvest the Little Sisters is the ability to gain a greater amount of ADAM from them; by rescuing them instead, you receive less from them directly, but they will also offer you gifts of ADAM which make the total amount obtain greater than harvesting them would have been.