When we talk about understanding, surely it takes place only when the mind listens completely - the mind being your heart, your nerves, your ears- when you give your whole attention to it.
Living in the moment means letting go of the past and not waiting for the future. It means living your life consciously, aware that each moment you breathe is a gift.
There is no success without sacrifice. If you succeed without sacrifice it is because someone has suffered before you. If you sacrifice without success it is because someone will succeed after.