One of the more hideous things you have to do when you have a book coming out is suck up to other authors in the hope they’ll give you a blurb for your jacket. Everybody in this process hates it: the people doing the asking, the people being asked, the third-party friends leaned on to lean on their own contacts. And yet, in the absence of any better ideas, the quote economy chugs on.

I’ve been thinking about blurbs lately, not only because my own galley is out for approval, but because of two recent references to the practice, both of them exceedingly grumpy. The queen of the gentle letdown was the writer Nora Ephron, who – I just looked up an email I received from her many years ago – would respond to friends and acquaintances begging for endorsements with the joke that she gave up giving quotes when her gynaecologist “wrote a book and asked for one”; or her vet, or other versions of a line that evolved over the years and that, with characteristic generosity, she used to make the asker feel slightly less of an arse.

At the other end of the spectrum is the novelist Rose Tremain, who said in the Times last week: “I hardly finish any books. Our so-called literary world is now choked with the mediocre and the banal, piles of which arrive through my letter box, soliciting endorsements, every week.” One feels her pain: no one wants big slabs of text dropping uninvited on the doormat. On the other hand, cheer up, Rose – maybe one day these dreadful people will go away, and then you’ll have problems indeed.

Meanwhile, Susan Orlean, of the New Yorker, wrote rather crossly on Twitter that those asking for blurbs should observe some basic rules, among them: “1) Tell me when you need it. I don’t have the power to magically know this date. 2) Don’t praise my ‘novels’. I don’t write novels” – although she had the grace to acknowledge that “everyone hates asking for blurbs”, begging her own publisher to let her off the hook in the run-up to her forthcoming book.

They won’t, of course. Either everyone has to quit, or no one can. These days, I find myself looking at blurbs less as a measure of the book’s worth than of the benevolence of the names who provided them. Hilary Mantel is a legendary blurber, lending her name to a wide range of titles; Jonathan Franzen, for all his assumed unapproachability, is a veteran blurber over the years and I’ve always thought must be a good egg for that. And while I have found myself being sniffy about Salman Rushdie’s profligacy in this area, in my current mood it strikes me as chivalry of the highest order.

Even so, one can have too much of a good thing and I’m always suspicious of a book with too many actor, politician or rock star names on a jacket, which makes me admire the writer’s networking skills and assume the book will be terrible.

“I blurb only for the dead these days,” was a line reportedly used by Margaret Atwood many years ago, confirming my view: while giving a good blurb is a noble act, a good letdown is a work of real genius.

• Emma Brockes is a Guardian columnist