The question as to how musicians manage to come up with interesting song lyrics is a very commonly asked one in music circles. You may not see where the question comes from, until you sit down one day; and try to come up with some sort of song lyrics that can impress anyone else, but you. Then you will see just how difficult a task lyric writing can be. All in all, though, musicians manage to come up with interesting lyrics by remaining attuned to their environments for inspiration, and consciously looking for correlations between things. This way, for instance, a musician seeing a man with a potbelly gets inspired to write a rap lyric about male pregnancy (if it were to become possibility somehow, for instance), with such a song - that forces people to laugh and think beyond the convention - having a tendency to become a major hit.