The Vinegar Tasters.
Confucius, Mencius and Laozi taste vinegar from the same pot. Their perception of its quality is determined by their philosophy, and shown in their facial expressions: One sour, one bitter, one sweet. So it is with life -- even in the same situation, different people will react differently based on their outlook on life.
To me, the painting is a reminder not to fill myself with bitter or angry thoughts. There are many things wrong with the world, but these can simply be stored as facts, rather than dwelled upon and thereby passed on to others in anger.
Consider the story of the vinegar pot as an allegory for social media, perhaps.