Cognitive scientist and author Guy Claxton writes in The Heart of Buddhism: Practical Wisdom for an Agitated World (1999):

Buddhism does not tell you to pull your socks up and be nicer to everybody, nor does it wag a stern finger at you when you behave badly or thoughtlessly. The fundamental problem is not of sin, but of delusion, and the way forward is therefore not through the uncomfortable shove that guilt is supposed to provide, but through insight. So the initial sense is of working on yourself for yourself.

It would be a big mistake, though, to suppose as some critics do, that because Buddhism starts with oneself, it also stops there. Far from it. Buddhism tells you that if you work at it you will be happier and kinder. Being a ‘good person’ is not a matter of denying yourself but of knowing yourself, and the better, the more clearly, you know yourself, the more everybody wins. Thus although many people are drawn to Buddhism for ‘selfish’ reasons, they discover that the package deal on offer includes a greater sense of natural concern for others, as well as the anticipated peace of mind.