Here’s a confession. When I was a child, I used to think that Dusty Springfield was singing, “You don’t have to say you love me, just because a ham.” This made no sense to me, of course. If an adult had challenged me on it – “Just because a ham?” – I’d have been at a loss to explain myself. But when I was a child, many such things were mysterious, and I happily watched them as they flew over my head. Eric Morecambe’s joke about the two old men sitting in deckchairs made me laugh even though I didn’t understand it; bizarre and grammatically out-of-place references to pork products in love songs were totally fine. And so I sang along. “You don’t have to say you love me, just because a ham. You don’t have to stay forever, I will understand.” Seventy-five per cent of that couplet was very clear to me. Seventy-five per cent was excellent.

The meaning of song lyrics in our lives has been much on my mind because I’ve just made a programme about Joni Mitchell for Radio 4. I have revered Joni as a songwriter since the days of Ladies of the Canyon in 1970; her music and lyrics are woven into my memory and imagination. Whenever I see an image of a helicopter alighting on a building, I think of Joni’s image from “Harry’s House” on The Hissing of Summer Lawns, “A helicopter lands on the Pan Am roof, Like a dragonfly on a tomb.” Thoughtfully, she always printed the lyrics on the album covers, as well as providing a self-portrait or two – her words were precise and poetic, and extremely memorable. “I could drink a case of you, and I would still be on my feet.” “They paved paradise, put up a parking lot.” “No regrets, Coyote. We just come from such different sets of circumstance.”

But once I started work on the programme, I discovered that for many of her fans, Joni’s lyrics weren’t just vivid and true. People actually felt that Joni was describing their own lives. In fact, so prevalent is the view that Joni was less original artist, more psychic channeller for other people’s emotions that after a while I started to worry I had missed the point of Joni Mitchell all along. Because, call me self-effacing, but I never thought Joni was even interested in my own paltry love life. To me, she has always represented a worldly, glamorous and hugely talented woman with life experience far advanced of my own. I eagerly received her messages, as if from a distant star. Yet evidently, when listening to Joni, the correct response to a line like, “You are in my blood like holy wine; You taste so bitter and so sweet” is to say, “Yes, yes. You see, she writes about me so well.”

Is it necessary for lyrics to reflect our own lives back to us? Well, many great songs do not. I challenge you, here and now, to tell me a) precisely where Wichita is, and b) how much time you have spent there as a lineman. Have you ever been through a desert on a horse with no name? Is it even true that the first cut is the deepest? (No. In fact, as a generalisation, it’s patently questionable.) What would “a whiter shade of pale” actually look like? Where is Blueberry Hill, and can anyone go there? If it’s self-evident that you can’t always get what you want, does it logically follow that, if you try sometimes, you might find you get what you need?

The great quality of famous song lyrics is that they file themselves so efficiently in our brains, and then pop up to the surface when we need them. For example, a while ago I was going through a traumatic professional break-up and found myself humming, “You’re Gonna Lose That Girl” (The Beatles, Help!), which not only fitted the situation, but completely cheered me up. It is amazing how often the right, consoling lyric comes to mind. Being in love with my dog, I often can’t resist the impulse to snatch him up and waltz him around the kitchen singing “It’s All About You” by McFly. And as for “We Gotta Get Out of the This Place, If It’s the Last Thing We Ever Do” (The Animals) – well, I reckon that’s probably Number One in my Top 500 instant mentally recurring lyrics.

With age comes enlightenment, sometimes. The lyrics that we blithely sang along to in youth can turn out to be more heavily loaded than we thought. I mean, have you ever asked yourself what “Please Please Me” is actually about? (You might want to lie down.) I also now think, with the benefit of experience, that Dusty Springfield’s “You don’t have to say you love me; Just be close at hand” is one of the saddest sentiments ever expressed in song. But I wonder if we should, as a general principle, be a bit more choosy about letting some of these lyrics worm their way into our subconscious in the first place, when such mental space might be finite. Do I really care, for example, that once at night Cotillion squared the fight and she was right in the rain of the bullets that eventually brought her down? I mean, now that I recognise that the lyrics to “Heroes and Villains” are utter nonsense, isn’t it horrific to realise that they won’t ever go away?

Lynne Truss’s programme My Muse: Joni Mitchell is on Radio 4 on September 18th