There are many reasons why a student might grow quite fond of Sir Walter Raleigh's "The Nymph's Reply to the Shepherd." First, it is a direct (and somewhat sarcastic) reply to Christopher Marlowe's "The Passionate Shepherd to His Love." In the latter poem, the shepherd offers all kinds of incentives for the nymph to come and live with him and be his love. He will give her all kinds of pleasures and lovely things. But the nymph is smart and practical, and in Raleigh's poem, she reminds the shepherd that none of the things he offers her will last. Those posies and roses and those fancy clothes will be gone before long.
What's more, the nymph can recognize that the shepherd's love is not true. He has a "honey tongue" but a "heart of gall." This is a wonderful set of contrasting metaphors that show that the shepherd is not what he seems to be. He wants to convince the nymph of his love, but his love is fickle and mostly lust. If the nymph goes with him, her "fancy's spring" will quickly turn into "sorrow's fall." If she could be sure of lasting joy and lasting love, perhaps she would take the shepherd up on his offer, but as it stands, she knows better.
This poem also contains some appealing poetic devices. Notice the alliteration throughout the poem. Alliteration occurs when the initial sounds of words match. Most lines in the poem contain alliteration. Look at line three, for instance: "These pretty pleasures might me move." Here is an example of double alliteration on the p and then on the m sounds. The line "Is fancy's spring, but sorrow's fall" even turns the alliteration into a mirror pattern with the f alliteration on the outside and the s alliteration on the inside.
The poet also employs repetition for emphasis. The words move, love, and live are all repeated multiple times. These also allude Marlowe's poem and thereby enhance the nymph's response. The poet borrows many other words from Marlowe's poem as well, again intensifying the reply and making it just a bit mocking.
Finally, the poet uses plenty of interesting metaphors. We've seen a couple above, but the line "In folly ripe, in reason rotten" is another prime example. All of the shepherd's promises are ripe with folly but rotten in reason. The idea here is that like a piece of fruit, these promise look good for a while as long as a person buys into their foolishness, but if someone really starts to think about them using reason, they see that they are rotten to the core.