Then the label calls. They've heard some of what you're doing with this song, and they like it so much they want to put it out as a single. That's great, it's a wonderful song, but it's a minute too short to be a single.
What can you do? Adding a verse is right out; it'll disrupt the perfection of the song. It doesn't work at a slower tempo; you'd have to slow it right down to snoresville to get another minute out of it. Anyway, your studio time is running out, you gotta get this done today.
And then you get a bright idea. All you have to do is repeat the chorus and fade out over a (long, excruciating) sixty seconds, but to keep people from being bored, halfway through, you kick it up a key. Walla! Musical perfection.
... Except not. Such a cop-out is apparently known as the Truck Driver's Gear Change, and some people want you to cut it the heck out. It seems as though the worst repeat offender is Michael Jackson, but no genre is safe, except perhaps "that hippity-hoppity stuff all the young coloreds really like these days" [/