If At First You Don't Succeed…

Try, try again. Repetition is the key to this poem: it's only by shoving his age in our faces at every possible turn that the speaker is able to slam home the point that he was pretty dumb when he was 21. Subtle? Not exactly. But if you've listened to the same commercials over and over, chances are you'll start to remember a company's slogan. In this case, repeating our speaker's age reinforces just how stubborn and unchanging he really is.

• Lines 1, 8, 9: These lines repeat various forms of the "when I was one-and-twenty" refrain, making sure we realize how important it is.
• Line 15: Here it is: the non-repetitive line. We know it's important because it's almost syntactically identical to line 8, which makes its differences even more apparent.
• Line 16: Ending the poem with a repeated phrase makes us think that he's summing up an argument. As it turns out, he is!