Yes, it might be a bit much to presume.
I promise you, no matter what you do in this life, someone somewhere will say, "what do you want to do that for?"
And when things go wrong, there will be plenty of people who will say, "I'd never do that". And the answer is, no, you wouldn't.
I got into a class discussion once about this notion. They had recently been with a teacher who taught some current theory that everything we do is done for some personal reason and that there is no such thing as altruism. I suggested that this was a rather skeptical point of view, to which they agreed.
I then explained the entire notion of Christianity is to do “good works” so that Christ gets the glory (and not the individual doing the act). They didn’t know what to think of this.
1Co 10:31 Whether therefore ye eat, or drink, or whatsoever ye do, do all to the glory of God.
Col 3:17 And whatsoever ye do in word or deed, do all in the name of the Lord Jesus, giving thanks to God and the Father by him.