This is, I think,
the difference between sad and poignant:
Sad is the sight of a dead dog, hit by a car and left there on the edge of a neat little yard, in front of a small house.
Poignant is the sight of a dead dog, hit by a car and left there on the edge of a neat little yard, with another dog, standing next to him, barking at the sky.
Something about the other animal makes the scene more compelling and more personal. Poignancy is an event that transcends a private situation and makes it meaningful to many people.