The problem with characters in TV dramas is that they never watch TV dramas. Or, at the very least, they never learn the lessons that the rest of us pick up from TV dramas.
Lesson number one: if you have letters that you do not want your husband to see, do not leave them in a box in your bedroom, where he will stumble across them while hunting for a needle and thread. Lesson number two: if you are functionally illiterate, work out your excuses in advance.
Neither JJ nor Lisa appears to have seen a TV drama. They are the couple at the centre of Love Letters (above), the first of five stand-alone mini-dramas in BBC One's Secrets and Words series focusing on the problems caused by adult illiteracy.
So we see JJ struggling to explain to a client why he cannot provide her with a receipt. Then, looking to replace a button on his shirt, he comes across a box full of handwritten letters. He is just about literate enough to make out three damning details: the letters are addressed to Lisa; they are signed "T xxxxxxxxx"; they span years.
And so JJ asks Mrs Taylor, his daughter's teacher, to read them for him. The letters are personal, she says, and refuses. Instead, she offers to teach him to read them for himself.
Gradually, JJ realises that reading is not as scary as he thought. Mrs Taylor - who is Fiona by now - then suggests that they meet in the public library after dark. In the kind of gesture one only makes with a team of set-designers to hand, she decorates the shelves with hundreds of tea lights. The message is writ so clear that even JJ can read it.
It is all very nice, but also quite worthy and earnest, as though decent plot is less important than Message. Frankly, it is just a bit theatre-in-education. Still, perhaps the other four episodes will be better, I think, and watch number two.
In Help Me If You Can, a semi-literate single mother takes a job in a pharmacy. Her boss, Ray, washes his face and stares in the mirror a lot. This demonstrates that he is in pain. Other characters reveal their salt-of-the-earthiness by saying things like: "She's just trying to make something of herself. There's no shame in that." The heroine, meanwhile, quotes the Children and Young Persons Act, thus proving that illiteracy is not at all the same thing as stupidity.
"Sometimes I wonder: what's the point?" says Ray, about two-thirds of the way in. I could not have put it better.
Secrets and Words starts on BBC One on 26 March at 2.15pm.