Clock of life, thought experiment. List a few examples for us — Outlander
You should look to improve yourself for the sake of humanity, not because of yourself. Find the strengths and weaknesses you have and decide a path, that works for you. You shouldn't look to benefit yourselves, like our current society works, because that causes a lot of problems. When you benefit other individuals with your actions, they will benefit you, because you have been of benefit for them. If we act in a way that is beneficial to others, those benefits accumulate and you will always gain more back, hence you could call it investment instead of sacrifice.
Is that really a sacrifice then or a mere investment? — Outlander