The speaker of "I measure every Grief I meet" spends a great deal of time wondering about other people's emotions. Not only is she exploring their grief, she is also exploring several other questions: What is the nature of grief? How do others experience grief? Can grief ever end, or does it last forever? What are the different reasons that people experience grief? These questions are never answered completely; rather, the speaker explores various possibilities without ever closing in on definite answers.
While the poem begins with a tone of certainty, it ends in uncertainty, showing that exploration only leads to, well, more exploration.
Exploring the sadness of others is a way to ease the speaker's own sadness. Creepy? Yes. But effective.