For many people, spending most of the time being with other people (family, friends, community and other communities), focusing on bonding, socializing, interacting, connecting, sharing, knowing, eating, drinking, talking, listening, looking, laughing, playing, empowering, encouraging, aspiring, inspiring, remembering, projecting, anticipating, expecting, creating, planning, plotting, suggesting, contributing, commenting, complimenting, criticizing, gossiping, complaining, entertaining, enjoying, doing social/community activities together, upgrading their quality of life/standard of living, fulfilling passionate desires and achieving personal worldly ambitions and spiritual or religious goals, getting involve with achieving a world that complies to a particular vision, to attain the sense of in control, satisfaction, goodness and meaningfulness, is living life. For them, "This is a better meaningful way of life."
For some people, being by oneself most of the time, as much as possible, focusing on one's action, practice, duty and responsibility, talk less or talk nothing, without commenting on worldly affairs, or gossiping about other people's affairs, or criticizing/interfering with other people's different ways of life, thinking, belief, action and reaction, minding one's life and one's mind, being at peace unconditionally, respecting everyone being what they are, as they are, neither admiring/praising certain qualities that appear to be superior than others nor condemning/criticizing certain qualities that appear to be inferior than others, and stop contributing impurities, unhappiness, unrest, anger, hatred, jealousy, dissatisfaction, disappointment, grudges, conflicts, discrimination, violence, disharmony and disturbance into the surrounding environment or the world, is living life. For them, having peace in one's mind, being free from desire/hostility/animosity/fear/intimidation/offensiveness/defensiveness is the highest form of contribution to the society or the world peace. It's nothing to do with "This is a better meaningful way of life." or "Other ways of life is less good and meaningless."
There's nothing selfish about that at all, though for many people, the part of 'not mingling/mixing with the society without getting involve in any form of social activities' might appear to be 'selfish', or 'rude', or 'unhealthy', or 'non-progressive', for those who believe in a better world is about 'all human beings should be getting involve with the social activities', 'community contribution' and 'worldly activism', where they need as many other people as possible to get involve in their social activities to be supporting, cooperating and working with them in order to create a 'better' world that they think how it should be.
Either wittingly or unwittingly, there will always be some people would want to interfere with others who are different from them, whom they dislike and disagree with, and they would try to influence/control/covert/discipline/condemn/punish other people who don't support or follow their vision for creating a world that they desire, that complies to their liking, values, vision, thinking and belief.
Yoga and meditation practitioners are about having unconditional peace in oneself as contributing peace into the world by focusing on looking after, purifying and quieting one's mind, and it's never about trying to influence/control/convert/discipline/condemn/punish others to also be like oneself to make a 'better' world that complies to one's liking, values, vision, thinking or belief, especially those who have realized Impermanence and Selflessness.
The world doesn't belong to anyone. Many people would think and believe that the world belongs to everyone, and hence, it's everyone's duty and responsibility to 'cooperate together' to make the world 'a better place', but how true is that? The standard and meaning of 'a better place' is according to whom and what? Different people desire a world that complies with their own particular way of life according to their own liking, values, vision, thinking and belief. If everyone insist on making the world to be the way that they desire, that they think how it should be, what will happen in the world? People are getting frustrated and fighting against one another, to over-power one another, in order to create a world that they desire. Even so, it's everyone's freedom for their thinking, belief, desire, action and the consequences of their action.
Swami Sivananda taught, "Even if all the leaders are taken out of the world now, the world will run on smoothly, probably more smoothly. Even if all the people retire into the forest, the world will go on."
The world is so quiet and peaceful when everyone have gone to sleep and there's nobody performing any actions in the world with the great aspiration to make the world to be in any particular way that different people desire and think how it should be.
In yoga, it's not about the sense of duty and responsibility towards the world, but out of compassion, love the world as it is, not necessarily the way that 'I' desire it to be. One doesn't claim possession/ownership towards the world, being ambitious to make the world to be the way that 'I' desire it to be and the way that 'I' think how it should be. One just do one's best to be looking after one's mind, to stop contributing impurities and unrest into the world, and respecting the law of nature - Impermanence and Selflessness.