Perhaps my favorite verse in the whole bible is found at Rom 15.3: For Christ did not please himself; but, as it is written, "The insults of those who insult you have fallen on me." I enjoy this verse so much because it seems to me to summarize in nuce the whole of the Christian gospel; God's selfless goodness and grace in Jesus Christ, who did not seek to please himself but instead acted for the good of others, to bring them life and peace and salvation.
There are plenty of examples of this available in the gospels. Consider the feeding of the five thousand recorded in Mark 6.30-44. The story begins with Jesus and his disciples, who've just returned from their mission throughout the villages (vv. 7-13). They want to retreat to a deserted place and rest for a bit, since their mission had probably exhausted them, and so many people were flocking to them that they had no time even to eat (v. 31). But when they retreat to a certain spot, many people recognized them and got there ahead of them (v. 33). Of course, since the masses arrived there before the disciples did, Jesus could not get rid of them.
Jesus and his disciples are exhausted and hungry; they want some time to themselves to relax and to regain their strength so they can go on serving the people. But they find a large mass of people has come to them when they wanted to take a break. What does Jesus do? Mark tells us: he had compassion for them, because they were like sheep without a shepherd; and he began to teach them many things (v. 34). Christ looks upon these miserable people with eyes of mercy and cares for them, even when it is the height of inconvenience for him to do so.
Jesus thinks nothing of himself, cares nothing for himself, does not seek to please himself, but instead always seeks what is the good of those around him. The paradigm example of this, of course, is the crucifixion: Christ there died for our sins (1 Cor 15.3), giving up even his life so that we may live. This is why I think "Christ did not please himself" is the sum of the gospel.
For Paul, too, it is the sum of Christian ethics: We who are strong ought to put up with the failings of the weak, and not to please ourselves. Each of us must please our neighbor for the good purpose of building up the neighbor. For Christ did not please himself (Rom 15.1-3). This is Christian ethics in a nutshell; this is more or less how we ought to live among one another.
Imagine what it would be if this attitude were prevalent in our churches! Imagine what it would be if we took this command seriously even for a span of a week -- how much we would get done, how much good we would accomplish! To think nothing of myself, not to seek my own pleasure and enjoyment, but to do what is good for my neighbor: that is the essence of a gospel-informed ethics. It is a short path from this to sainthood and to God himself, if we would only do it.
What does this look like? It looks like: not judging the other persons in my church who don't live up to the standards I set for them, but instead seeking to help them and encourage them in all their ways; helping the persons in church whose problems are the gravest, praying for and with them, rather than gossiping about their failures and their sins; indeed, praying for persons who bother me and even who harm me and do me great evil, rather than fighting or speaking evilly of them or seeking revenge.