Immediately after Beyoncé's blistering gig at Glastonbury (loved by most of the 2.5 million watching on TV if the Twitter praise was any guide) the BBC returned to the studio where host Zane Lowe promptly, gruffly dismissed the performance. Not quite in keeping with the national mood, which had the performance by the pop diva down as one of the best in the festival's history. Here, Observer critics reveal when they, too, failed to anticipate a groundswell of public love for something they've reviewed...

Kitty Empire: Pop

I remember giving the first album by Justin Timberlake a bemused, lukewarm review. Not only did Justified go on to sell 7m copies; I also ended up thinking it was ace. The production was top-notch – wall-to-wall Neptunes and Timbaland at the heights of their powers – and it helped Timberlake break the boy band mould.

Jason Solomons: Film

The tide of global opinion about Titanic clearly shows that this was a powerfully emotional work, and Leonardo DiCaprio's little face made girls around the world weep. I could never have predicted this on suffering the first press screening and that dreadful Celine Dion song. Although I still don't think James Cameron can write dialogue, and Titanic is still not a very good movie, he gave the public something they yearned for without them even knowing it and they fell for it, hook, line and, er, sinker.

Robert McCrum: Books

When I was the Observer's literary editor I flunked completely with Naomi Klein's No Logo. Our short, rather dismissive review missed the point of the book (as I had done). I spent the next two years watching No Logo become a cult classic.

Susannah Clapp: Theatre

In a week when Kevin Spacey dominates the stage of the Old Vic, I look back a bit ruefully to my review of him in The Iceman Cometh 13 years ago. It praised Spacey but it didn't get the measure of him; went no way to foreseeing the influence he was about to exert on London theatre.

Kate Kellaway: Children's books

In 1997, I picked up a book called Harry Potter and the Philosopher's Stone. I judged it to be hackneyed although I could see it was incident-rich, with a roll-on narrative that reminded me of the way children play. I damned it with faint praise. Since then, Harry has come flying back to knock my verdict off its feet.

Euan Ferguson: TV

I was pointlessly rude, years back, about Early Doors. I grew to love it, gentle and clever, even bought the boxed set, and wish, as with much in life, I hadn't settled for being lazy and cheap in my review. I was also pointlessly wilful when it came to ignoring Mad Men for years because of the drooling hype.

The Guardian