I also find it important to consider what they think of as "benefitting themselves".

If good vs bad is dependent upon their actions, then someone extremely selfish can be seen as "good", just if they have enough ability to think long term and desire a future that would end up making them act "good".

If good vs bad is dependent upon their thoughts, then good luck finding out what people think. What they say will be completely different from what they think and a lot of them just realise they can easily get away with contradicting themselves as long as they do so in front of someone powerless.