Stanza 1 Summary

Get out the microscope, because we’re going through this poem line-by-line.

Success is counted sweetest
By those who ne'er succeed.

We start off with a lesson of sorts.
The poem's speaker lets us know that only those who "ne'er succeed" can most appreciate the concept of success.
To put it more directly: you have to be a real loser to truly appreciate success.
That, friends, is a paradox. How can you most appreciate something that you don't even have?
And yet, we think that that speaker makes a certain kind of sense here. It's the folks who never get to experience the satisfaction of success who will most want that feeling.
If you're into sports, you might think about how hard it is for defending champions to repeat, since they have to fight off all the players who want that success that they've never had a chance to experience.
If you're not into sports, try substituting any of the following instead: spelling bees, business ventures, literary awards, chili cook-offs—you get the idea.
The use of the figurative adjective "sweetest" here really drives home how important success is to those who can't attain it. It's as though they can almost taste it.

To comprehend a nectar
Requires sorest need.

Hmm—here we're presented with a bit of a puzzling metaphor.
The literal translation here is that you have to be really, really, really thirsty ("sorest need") in order to fully understand ("comprehend") a… nectar?
Was Dickinson a juice fanatic or what?
Probably not—she was more than likely using "nectar" in a more general sense. In classical literature, nectar was the gods' beverage of choice—kind of like a divine Diet Dr. Pepper. In this sense, then, nectar really means anything you would really like to partake of.
In order to even understand what you desire, argues the speaker, you have to want it, and not just a little bit.
As we look back on this stanza, we're given two examples to illustrate essentially the same lesson: in order to really appreciate something, you a) can't currently have it and b) have to need it real bad—like Napoleon's chap stick.
We should also point out that we have some rhyme and metrical patterns starting to emerge here. We say a whole lot more about that over in "Form and Meter."