Well, there's lots of words in the existing database, but not *all* the words. "Slight Figure of Speech", for example, isn't in the database yet and returns a "no records found", but "Slight Figure" returns a forum post using the words "figure" and "slightly". "Slight Of" returns 10 forum posts, none of them titled "slight of" anything.
Though of course now, or whenever the index updates, "slight figure of speech" will return this forum post.
If a search result looks wrong, try opening the odd answer and CTRL-F for the individual words in the search. That's how I established that all the words you typed are in the result you got. (Someone typed the full lyrics to two versions of the song into the comments field, and it's a long comments discussion, so that particular entry probably generates a lot of false positives. This might be an argument that the comments field shouldn't be searched outside the Detailed Search.)
Now, if they're not there, that would be a very interesting indexing error. But in this case they definitely are.