Love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you.
If someone strikes you on one cheek, turn to him the other also. If someone takes your cloak, do not stop him from taking your tunic. Give to everyone who asks you, and if anyone takes what belongs to you, do not demand it back. Do to others as you would have them do to you. "If you love those who love you, what credit is that to you? Even 'sinners' love those who love them. And if you do good to those who are good to you, what credit is that to you? Even 'sinners' do that. And if you lend to those from whom you expect repayment, what credit is that to you? Even 'sinners' lend to 'sinners,' expecting to be repaid in full. But love your enemies, do good to them, and lend to them without expecting to get anything back. Then your reward will be great, and you will be sons of the Most High, because he is kind to the ungrateful and wicked. Be merciful, just as your Father is merciful. (Luke 6:27-36)
I can't add to that.
The first sentence...this is the advice I just gave my youngest in response to a situation he's having with a difficult teacher. "Love her and do your best. Turn in all of your assignments. Smile and be pleasant."
I have found this to be extremely helpful in the workplace.
"Love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you." Words to live by.