Before we even think of infinite altruism. Think of whether we are taking care of ourselves well, I mean, really well. Most of us do take care of ourselves really well, externally, of course. We take care of our outer appearance, our wealth and possession, basically everything we can see, and others can see.
But more importantly the inner, that which cannot be seen, have we take care of it well? Or well enough? The reason is it will become a burden to others if we don't take care of us well. It is also about responsibilities. Responsibility of ourselves on ourselves.
Then at the same we start looking out, towards others. When we give and help, we should think of this 'will benefit others?, it is an unconditional giving and help, that is not for a reward'. We do need to think in this way consciously. Because in reality the actions might not benefit others. People might acted in ways that we see them as more selfish or become unfriendly towards us. If we become angry, or regret how did we end up trying to be good or helpful to others, then it is because we have some expectations, the worldly kind, like expecting for a reward, it can be praise or friendship. Knowing that we modify our motivations the next time we give and help. We think through our to them in more ways, instead only this way or that way.