In today's first reading Paul provides us with a long list of commands
Let love be sincere;
hate what is evil,
hold on to what is good;
love one another with mutual affection;
anticipate one another in showing honor.
Do not grow slack in zeal,
be fervent in spirit,
serve the Lord
Rejoice in hope,
endure in affliction,
persevere in prayer.
Contribute to the needs of the holy ones,
exercise hospitality.
Bless those who persecute you,bless and do not curse them.
Rejoice with those who rejoice,
weep with those who weep.
Have the same regard for one another;
Of the entire list it's the third from the bottom that may be the most difficult
Bless those who persecute you,bless and do not curse them.
It's worth noting that he felt the need to repeat himself, just so you didn't miss it.
While this may be the hardest, it should be the easiest. After all, if someone is persecuting you, if they are hell bent on making your life miserable, the only real way to make it stop is for them to have a change of heart, and the only one who can really change hearts is God.
Rather than caving in and crying, or getting angry and doing something stupid, we, as Christians, are called to pray for our persecutors. Pray that God will touch their hearts, and bless them. Pray that God will fill their hearts with his love and bring about true conversion in them.
Truth be told, persecutors are never happy people. No matter how they disguise it, underneath they are unhappy people taking out their unhappiness on others.