Even though I believe that being judgemental is not the best thing to do; I do it all the time under the cover of 'discernment', by subconsciously (or even consciously!) classifying people as good and bad. During my childhood, I had always believed that people behave in a certain manner depending upon some intrinsic value which is highly influenced by how and under what circumstances they were brought up. I had decided that every jerk I meet; I will try to cut him (or her) at least some slack just because they might have had an unfortunate childhood, unlike mine. As I grew up and read more economics, I started thinking that the most rational thing to do was to be good. I believed that if I was good to people, they were bound to be good - not because of my (or their) belief in Karma or their conscience or any other so called spiritual concept but because it's in their best interest too (at the very least). What then incentivises people to be not good? There can't be contradictions. I needed to check my premises.
I did not cheat in exam; I knew more than enough by myself. But I have no idea of how I would have responded if I had to cheat to be able to barely pass the exam. I return someone's wallet lying on the road. Is that because I am a good person or is that because I have enough money? Would I have returned if it were, let's say something that might matter to me more than money or might be unaffordable, an antique painting? When I talk nicely to people; is it because I am a good person or is it because I enjoy their reciprocation of love and respect for me (friends) or is it because I can't afford to mess up with them (foes)? Would I talk to nicely to someone I do not deem worthy enough of either being a friend or a foe? When I let go things that make me feel bad, is it because I am not egoistic or is it because it's in my best interest to let go? Is it in the future anticipation of my behaviour due to which others might have to let go?
The very premise that good behaviour doesn't have a cost associated with it is what fails the theoretical concept of it being the best thing to do. More so, it has different cost for different people and hence, the varied responses. It's expensive, rather unaffordable to indulge in the luxury of being good.