I was just watching a video on Moral Development (subtopic of Developmental Psychology) that I'm reminded of. It's about how children/people develop morals. The focus is on how they arrive to a conclusion regarding a dilemma (a man steals heavily marked-up medicine for his dying wife)...how do you justify the action of stealing?

The stages (according to Kohlberg's theory) go from preconventional (what is the consequence of my action? e.g. the man shouldn't steal because he might go to prison) to conventional (what would society think? e.g. the man should steal to be a "good husband") to postconventional (what are my overall ethical principles? e.g. committing a small crime for the greater good).

Postconventional is where we start to consider "social contracts" and "abstract ethical principles" which I think relates to this showerthought.

And Developmental Psychology is about how we become to be who we are in terms of physical, cognitive, social and emotional factors. So I would say that your reasoning and justification for morally grey scenarios is a defining characteristic of you but probably not the "main part" because there's so much to psychology.