"The title? Let's see… we're sure it's around here somewhere. It's not at the top of the poem—nope. Maybe it's in the table of contents. No table of contents either? Well then let's just use the first line and call it a day."
We can imagine Dickinson's editors having a conversation like this. Since Dickinson wasn't big on publishing her work when she was alive, titles weren't that important to her. Even when this poem first came out in the Brooklyn Daily Union, its title was—wait for it—"Untitled."
Instead, subsequent collections of Dickinson's work have gone with the first line for a title, followed by a number. Depending on the edition you're reading, that number either represents the order in which the poem was found in Dickinson's original fascicle manuscripts (check out "In a Nutshell" for more), or it stands for the chronological order in which they were written.
In either case, a number is going to tell you as much about the poem that follows as a title like "Untitled" will.
So, let's go with that first line, shall we? We shall. "Success is counted sweetest" is, if you ask us, a pretty sweet choice to start things off. It establishes the poem's main focus ("Success"), describes the main dynamic of how it matters to people ("is counted"), and finally ends with a twist: "sweetest." We don't normally associate success with being "sweet"—unless we come from southern California, brah, and then everything is either "gnarly" or "sweet."
This kind of strange adjective, though, is pretty typical of a Dickinson poem. It really drives home how much success can mean to those who never get to experience it. The suggestion of a word like "sweetest" is that these poor folks can figuratively taste it. That reminds us of that old expression: to want something so badly that you can "taste" it. It's like that thing (success in this case) is right there, on the tip of your tongue.
And yet—no soup, or ice cream, for you. That's the true tragedy that this poem is describing.