there are many different ways and degrees to help.
not everyone can be mother theresa...but helping out of anger...that would be very draining, i would think. it depends on where the anger originates...at injustice in the world, or because other people don't help?
i do believe there has to be some natural flow to help for it to be genuine and not out of obligation.
if you deplete yourself seriously in some way to help, sometimes that can be considered sacrifice, if you can tolerate it and do it willingly...if it it is just to prove something, it may be counter productive.