Commentary on Meditations: B6:31

Sober up, recall yourself, shake off sleep once more: realize they were mere dreams that troubled you, and now that you are awake again look on these things as you would have looked on a dream.

I'm sure it has happened to you.  You are standing in front of a large crowd, about to deliver a major speech.  You look down and you are completely naked.  You feel a rush of blood to your head and try to cover yourself while people point their fingers at you and laugh.  Then you wake up and find relief that it was just a dream.  Marcus advises that just as we are relieved when we wake up from such dreams and don't view them as any significant matter, we should view events that may disturb us in real life.