One common problem that happens to humanitarian types is that they become disappointed in humanity. They believe that people are good; then they see people act in all sorts of ugly ways. They start out wanting to serve humanity, then they decide that humanity is not worth being served, so they go to a place of existential despair.
This is a lot less likely to happen to Christians. Christians expect people to be bad. When people are good, it is experienced as pleasant surprise. So these people become much happier.
I heard a liberal woman say, “humanity is great, it’s people I can’t stand.” I heard a Christian man say, “humanity is vile, but people are quite all right.” In both cases we see a direct function of their beliefs. One believes in goodness of humanity and is disappointed in misbehaviour in people. The other believes in the badness of humanity and is pleasantly surprised by people.
Of course Christians can go wrong as well. One big problem I’ve seen in Christians is that they think that only Christians are good and the only wisdom is in the Bible, and that everything else is of the Satan. I’ve known many good people who weren’t Christians, and I have seen a lot of wisdom outside the Bible, both in science and psychology and in Eastern religious paths. In taking this stance one impoverishes one’s understanding of the world, and the people who do that are correctly regarded as being ignorant. Christianity however does not have to be practiced that way. The most impressive people I know were Christians and Jews who had taken an interest in things besides the Bible and thus had a much richer understanding of the world.
The correct way to practice humanitarianism is to remain compassionate to people while being careful of sin. Empathy does not mean joining the mafia out of compassion. Be as wise and snakes and as gentle as doves. Have compassion for people without identifying with the wrong in them.
This being done, humanitarianism can again become a value and something to strive for. And then one runs a much lesser risk of being disappointed in humanity and more likely to remain happy.