Catullus 51

Catullus 51 is a "translation" of a Greek poem written by Sappho. Sappho's original however, slightly differs from Catullu's adaptation.

Sappho's poem is highly personal, betraying her deep feelings for her lover. She is so infatuated that she even compares the man sitting next to her lover as a god. She describes in detail the qualities of her lover, from the "sweet murmur" of his voice to the "enticing laughter." Sappho asserts that she is so overcome by her deep feelings that she is even close to death.
Catullus seemed to admire Sappho, for he uses his poem as a sort of tribute or at least acknowledgement to her. Indeed, the opening line of his poem is a direct reference to Sappho's. Catullus also feels a deep, intense longing for Lesbia. He speaks of this longing as something that he cannot control, something that causes him so much pain that it "rips all his senses from him." Catullus and Sappho are both speaking of a feeling that everyone has felt at least once, a rush of love for someone who you might have just watched from afar.
However, Catullus differs from Sappho in his last stanza. While she fades away in the intensity of her love, Catullus stops abruptly and almost chides himself. He scolds himself for being in a state that has "previously destroyed kings and happy cities." Perhaps he has been rejected, and is angry at himself for spending so much time on a love that won't pay him much heed. Or even if his affair has gone well, he feels that he is just wasting his time - yet another feeling that people who have had experience with relationships can relate to.