The sacrifice which causes sorrow to the doer of the sacrifice is no sacrifice. Real sacrifice lightens the mind of the doer and gives him a sense of peace and joy. The Buddha gave up the pleasures of life because they had become painful to him.
In this day of wonders no one will say that a thing or an idea is worthless because it is new. To say it is impossible because it is difficult is again not in consonance with the spirit of the age. Things undreamt of are daily being seen, the impossible is ever becoming possible.