Citizen 1, Citizen 2, Citizen 3, Citizen 15, Citizen 1, “But this city is so dirty.”
So don’t be the first.
This advice doesn’t just apply to littering.
One person being being lazy, inconsiderate, rude . . . provides a bad example from which others take permission to follow suit.
Fortunately the reverse is true and good behaviour from one person provides a good example which inspires others to do likewise.