doodlejump: its not that he feels he’s forgoing the mitzvah, its a matter of perspective. Believe me, i know from a firsthand point how much a member of hatzoloh gives..!! I dont know if this is a good way to explain myself but i’ll try: one should eat a fruit to make a berach, not make a beracha to eat the fruit.
As far as a gift for a rebbe/morah, a parent is mechuyav to teach his child. If he cant for whatever reason, he hires someone. When you hire someone, you have to pay. And just like, lehavdil a manicurist or barber, many people feel the need to tip.