Whitman's "O Me! O Life!" is a poem of contrasts and, ultimately, a statement about the humble but irrepressible value of life.

The poem presents the first stanza as a question, which essentially asks how an individual can see his life in a meaningful light when one is drawn back recurrently to thoughts of how "foolish" and "faithless" human beings are. The narrator includes himself among the ranks of the foolish and faithless and suggests that all people are interconnected in a web of "sad [...] recurring" "empty and useless years."  

The second, brief stanza of the poem offers a concise rebuttal to the distress and angst of the first stanza. "What is the value of a life?" the first stanza asks. 

The value of a human life is that "you are here - that life exists and identity." Every individual has an opportunity to live, however sordid or recurrently lost he may be in his life, and as the collective life of mankind goes on every individual "may contribute a verse" to the larger story that is mankind. 

What is the universal theme then? Life is its own value, its own prize and explanation.  

The essential idea is that no matter how miserable the world seems (cities filled with the foolish) and no matter how disappointed you are with yourself (of myself forever reproaching myself), and despite the seemingly futile struggle (poor results of all), life is still worth living. By the end of the first stanza, the speaker is in complete despair. O me o life is similar to Hamlet’s “to be or not to be” speech. The question is “what is the point of living if everything seems so terrible.”

The answer is a very concise way of stating the point or the meaning of life which is life itself. That sounds tautological (redundant) but that is the point. Even in the darkest hour, at the bleakest times in history, life still exists and history goes on. There is hope in that basic certainty. This poem is a celebration of life itself; at the same time, it suggests that struggle is a part of life and there is meaning to be found through struggle and that simply by being alive, you have inherent power and potential to contribute to the history of your and all (universal) life.