There is a difference, subtle, but crucial. We do not believe in grudging sacrifice. To be a martyr may be holy, but to feel like a martyr is not. Sacrifice anything, up to and including your life, if you can give it joyously. But a gift given only in expectation of glory or reward is destructive to all parties involved.
Gifts are fine, even gifts that appear to others to be sacrifices.
But if the feeling of sacrifice is stronger than the feeling of satisfaction attained by pleasing another, then it is not a gift. Both the recipient and the Presence will be better pleased by a small thing given joyously than by a large thing given resentfully or grudgingly, or in expectation of praise. Nor is prolonged guilt useful. It is healthy to recognize one's errors and to learn from them. It serves no purpose to dwell on them past the learning, or to cause oneself misery over them.