Alright, let's put it in perspective.
Johnny makes 20k a year, pays X%. That X% could've made the difference between a better doctor, a better insurance, higher-quality food, et cetera.
Mary makes 250k a year, pays X%. That X% could've made the difference between her going to the Bahamas, getting 3 iPads instead of 2, buying a new Mercedes.
People need to stop thinking about brute percentages. It's quality of life that matters. If I have 1000 dollars, giving away 200 won't hurt as bad, in the sense of satisfying needs, as if I had 100 and I gave away 15.