Packer is talking about people who chose to be offended. Of them he says this:
"The attitude is somewhat like a man being hit by a club. Offended, he takes up a club and beats himself over the head with it all the days of his life. How foolish! How sad! That kind of revenge is self-inflicting. If you have been offended, forgive, forget it, and leave it alone."
Being offended is the dumbest thing ever. President Packer put it perfectly here, in comparing it to hitting oneself on the head. Notice that he gets hit by a club from someone else only once, and then the rest of the beating is done to himself, by himself.
I believe that this idea is lost to someone who is offended. They would probably feel that every club smash is being done by the offender, and that it is continuously the offenders fault that the offended is getting hurt.
What we need to do is recognize when an offense is made. It is not difficult because it is natural to feel flustered or upset at an offense. But then, at that point, decide that that is all you would like to suffer, forgive, forget it, and move on.
On my mission, I would often ask my companions for advice and tips in what I was doing wrong. However, I would always request that they give me the suggestions right before bed. I know myself, and know I have the tendency to feel hurt when I am criticized. But I also know that I like to leave everything in my bed and have a fresh start every morning.
I know that holding a grudge is like a poison that slowly eats away at a person. So let us resolve to be not offended and to be happy.