‘Humour has something liberating about it. […] Humour is not resigned; it is rebellious. It signifies not only the triumph of the ego but also of the pleasure principle, which is able here to assert itself against the unkindness of the real circumstances.’
Sigmund Freud, Der Humor, 1927
I am not sure what Freud would have thought of this advertisement, but he would surely have approved of the principle it represents: good-natured, liberating humour in the middle of a busy cityscape, at a time when many people are anxious about many things.