"Then said he unto the disciples, It is impossible but that offenses will come: but woe unto him, through whom they come! It were better for him that a millstone were hanged about his neck, and he cast into the sea, than that he should offend one of these little ones. Take heed to yourselves: If thy brother trespass against thee, rebuke him; and if he repent, forgive him. And if he trespass against thee seven times in a day, and seven times in a day turn again to thee, saying, I repent; thou shalt forgive him." - Luke 17:1-4 AV
When a Christians is expected to forgive his offender seven times a day, that means he should have a forgiving spirit. But on the other hand, a Christian should also strive not to be an offender, or God will chastise him for being a hypocrite. Christ does not say since you are all sinners, and can be hypocritical, so it really does not matter to lose your testimony here and there. Christ says, "It is impossible but that offenses will come: but woe unto him, through whom they come", it is a woe to all Christians who are careless about their testimonies.
It is not easy to be forgiving, particularly the offenses occur on a continual basis, and verse 3 offers some good advice, which says, "Take heed to yourselves: If thy brother trespass against thee, rebuke him; and if he repent, forgive him". It is biblical to rebuke the offender, and he may not even know that he has wronged you. In the secular world, some people are pushing their limits on those that allow them to do so. To challenge their behavior can stop their intimation. If this does not change the situation, there are other references in the Bible that we can use.
Verse 3 also talks about the condition of forgiving, which is the repentance from the offender. God does not open the gate of heaven and announces that the sins of everyone are forgiven, so everyone can come to heaven. A similar condition is applied to relationship on earth. The offender needs to go to the offended to apologize for the mistake that he made, to agree not to do it again, and ask for forgiveness. He also needs to compensate any damage if required.