"When you wake up in the morning, tell yourself: The people I deal with today will be meddling, ungrateful, arrogant, dishonest, jealous, and surly. They are like this because they can't tell good from evil."
This is not pessimism but psychological preparation. By anticipating difficulties, Marcus immunizes himself against surprise and disappointment. More importantly, he continues by reminding himself that he shares common rationality with all people and therefore has a duty to work with them, not against them.
This morning practice exemplifies the Stoic technique of premeditatio malorum—the premeditation of adversity. By visualizing potential obstacles before they occur, we reduce their emotional impact and maintain equanimity when they arise.
Marcus, writing as emperor of Rome while on military campaigns, demonstrates how philosophical practice serves not as escapism but as preparation for effective engagement with reality.
Source
Meditations - Marcus Aurelius