The more mentally prepared you are for challenges to your being in a serene state, the greater your ability to maintain this state. The goal to strive for is to be able to remain in a serene state even when other people say and do things that could potentially cause distress. Mentally practice remaining serene regardless of what anyone says. Knowing that you can do this in your imagination will free you from worrying about what anyone may say in the future.
-from Rabbi Zelig Pliskin’s book, Serenity, p.78