While you don't have to forgive everybody, you must be willing to forgive anybody, anytime.
We who have been redeemed by Christ have to cultivate the attitude that we are willing to forgive those that have offended us whenever they come and desire restoration through repentance. Listen to the implications of Jesus' words on the sermon on the mount.
21 "You have heard that the ancients were told, 'You shall not commit murder' and "Whoever commits murder shall be liable to the court.' 22 "But I say to you that everyone who is angry with his brother shall be guilty before the court; and whoever says to his brother, 'You good-for-nothing,' shall be guilty before the supreme court; and whoever says, 'You fool,' shall be guilty enough to go into the fiery hell. 23 "Therefore if you are presenting your offering at the altar, and there remember that your brother has something against you, 24 leave your offering there before the altar and go; first be reconciled to your brother, and then come and present your offering." Think about the situation. Jesus says there is a man about to make your sacrifice at the alter. The scene is of an observant Jew in the first century bringing his lamb to the priest to make atonement for his sins. He is meditating on his need for an atoneing sacrifice and as he waits for his opportunity to make the sacrifice, he remembers that there is someone who has something against him. What should he do?
 New American Standard Bible: 1995 update. (Matthew 5:21-24) 1995. LaHabra, CA: The Lockman Foundation.
Jesus says that reconciliation is so important that what he should do is step out of line, leave his offering and go and be reconciled to his brother. Message: There is no reconciliation with God without a commitment to reconciliation with one another. We are much more likely to remember how others have offended and engendered our anger than the reverse. So Jesus gives this illustration to drive home the point that true worship of God is accomplished only in the shalom of brotherly reconciliation. Put another way: Vertical reconciliation to God is directly related to horizontal reconciliation.
Enough for now. I have to go talk to my heavenly Father and ask if there are any horizontal relationships that are hindering my vertical relationship with him.