In "Cretin Hop," Joey Ramone (who I presume came up with the lyrics) repeats using "four" in (I guess it’s) the bridge:
Cretins wanna hop some more
All good cretins go to heaven
I’m not suggesting I don’t understand the need for ending on "seven" for the couplet’s rhyme. It certainly makes for easier writing; the next line essentially must end with "heaven" because it’s the only obvious word in English that rhymes. (Go ahead. Try to think of another. I’m not saying no such words exist, but how many just came to mind? Exactly.)
Were it that the line proceeded from where the sequence left off in the first couplet ("five-six-seven-eight"), the possibilities for coming up with a closing rhyme in the second couplet would be wide open, given how many words rhyme with "eight." I don’t know much about the band’s method of songwriting, but making the line end on eight would have made for a more drawn out process. And it wouldn’t have improved the song in the end result.
It may seem I’m implying seven allowed for laziness on the lyricist’s part, but really it proved to be efficient; sometimes the first thing that comes to mind is the best idea one will get, and when one is putting out two albums a year (as the band was doing back in 1977) one needs to get cracking.
However, I started talking about the repeated four. The thing about seven that distinguishes it from every integer up to ten is, of course, it’s the only number that is two syllables when pronounced. Thus any four-number countup (between one and ten) that includes seven will be five syllables long rather than four. To maintain the precise number of syllables of the first couplet’s first line, the second couplet’s first line would need to be one fewer number (only "Five-six-seven"). Not only would that seem unbalanced in the total amount of numbers sang in the lines, that would be only three accented syllables (spondaic and trochaic meter), whereas "one-two-three-four" is four accented syllables (dual spondaic meter).
Hence, to maintain the meter of the accented syllables (and to end with "seven"), four had to be repeated. The extra unaccented syllable at the end of four-five-six-seven not only allows for the rhyme but provides an increased level of complexity to the bridge; the singing of the two lines in the opening couplet is not exactly the same as the singing of the two lines in the closing couplet because of the squeezing in of that bonus syllable. It’s not something that consciously appeals to the listener, but it enhances the experience.
For those of you who know the song, go ahead and imagine it with just five-six-seven at that point. See? Not as good.
You never thought of the Ramones as that artistically complex, did you?
[Hey look. There's a link for leaving comments. Wouldn't it be fun to tell Doug how full of crap he is?]