Everyone is self-interested because they want to maximize their utility, and their utility is defined in different ways for different people and for different cultures. Morality and religion, I believe have the most in common, attributing to developing self-importance through heroism and sacrifice.
Re: Google search:
"late Middle English: from Latin moralis, from mos, mor- ‘custom’, (plural) mores ‘morals’. As a noun the word was first used to translate Latin Moralia, the title of St Gregory the Great's moral exposition of the Book of Job, and was subsequently applied to the works of various classical writers."
I like to think I have good morals because I naturally care about humanity, even though I don't identify with a particular religion. This is to the point where if I must inflict blame, I end up inflicting it upon myself, and throughout life realized that I need to stop doing this because there are people out there who have not had the opportunities I've had, and that I should do what I can to improve the well-being of humanity in tangible ways. So I blame systems. And I try to then fix systems. Most people part of the system don't even know the system is broken, so then you have to spend considerable amounts of time learning to communicate with people who are perhaps considered highly immoral to most people, yet may be moral to their immediate families, or people who are permanently ignorant. I attempt to better myself only in the hopes I can inspire others. Perhaps that is the only thing that keeps me moving on the day to day. I see fragments of myself in others that I hope to repair. I am also likely to be prone to attack from people that don't understand me, and I must be able to defend myself and my family in this case. I see people with greed and issues of violent desires and immediately think that they had tried to skip over some aspects of motivational development re: Maslow's Hierarchy of Needs - They didn't know where to find love, or food, or shelter, or safety, or acceptance, so it turned into something overly destructive, or, society prevented them from moving up so they had to fight for it. I see a world where we can heal, where we don't need to suffer because the truth is we have enough resources and we can make it work. This is all highly optimistic of me, but it is what I tell myself.
Alas, after all my efforts, if I cannot be as moral as I wish or intend, so be it. I'll spend more time with nihilist philosophy and build a cool Batman-esque hideaway and eat cupcakes all day every day. I'll be a female version of Banksy.