One of the many reasons that Emily Dickinson's poetry is both thought-provoking and universally appealing is that she masterfully unites readers in a shared sense of humanity.

In "A Bird came down the Walk—," Dickinson immerses readers in the simple beauty of nature. In this poem, she stops to observe a bird sustaining himself with food (a worm) and drink (dew). His motions are eloquently captured, from the way he hops sideways to "let a Beetle pass" to the way his flight looks like "oars [that] divide the Ocean, / Too silver for a seam." To be human is to be part of incredible beauty in nature.

In "I heard a Fly buzz—when I died—," the speaker is dying when she notes the sound of a fly in her surroundings. The contrast between the solemn moment of a convergence of her loved ones in the room of her impending death and the almost absurd buzzing of a pesky fly in this scene shows how distractible humans can be in all situations. Dickinson shows that to be human is to sometimes focus on things of insignificance.

In "I felt a Funeral, in my Brain," the speaker narrates a feeling of losing her grip on sanity. She explains that her thoughts keep "beating—beating—till I thought / My mind was going numb—." To be human means to sometimes experience moments when reason fails us and when we are trapped with our own thoughts of solitude and feeling "wrecked."

In "A narrow Fellow in the Grass," the speaker explains his conflicting feelings about encountering snakes. He (as she assumes a male speaker's voice in this poem, a "Boy") speaks of the snake with wonder in the beginning of the poem:

The Grass divides as with a Comb,

A spotted Shaft is seen,

And then it closes at your Feet

And opens further on—

One of the reasons why Dickinson's poetry is so thought provoking is because her poetry shows a sincere interest in reflecting about the individual and their place in the world.  Dickinson's poetry speaks to the condition in which people can connect.  She speaks about realities that prompt reflection in everyone because the situations in her poetry are ones in which there only profound thoughts and no distinct answers.  

In "I heard a Fly buzz- when I died," the poem's focus the potentially experience in death. This is thought provoking because death is a topic that impacts all, and yet so little is known about it.  What the fly moves towards is a realm in which there are only questions, akin to the experience of death.  What happens to the body and what happens to the soul are conditions in which there are no answers.  The fact that Dickinson takes a state of being in which there are no certainties is one of the reasons why her poetry is so thought provoking.  She is able to excite the sensibilities of thought in her addressing of topics that possess only thoughts.

In "I Felt a Funeral, in my Brain," the topic is mental breakdown.  This is yet another topic in which little is absolute and known.  The thought provoking topic of sanity and insanity is why Dickinson's poem incorporates so much thought.  The uncertainty that is present in Dickinson's subject area is part of the appeal in her poem.  There is nothing certain this realm.  With such ambiguity and doubt, Dickinson's poem lends itself to thought provoking reflection.  In choosing topics that are not absolute but rather far from it, Dickinson's poetry is thought provoking.