Personal opinion: I really dislike World Book Day
This may be more controversial than my posts on Brexit, but as an avid book-lover I really dislike World Book Day.
In particular, I dislike the way the primary focus of the day is about dressing up. I recognise that some people like dressing up - but we already have other days dedicated to dressing up, notably Halloween. There are also fancy-dress parties and other fancy-dress events. We have one day a year that's meant to be about celebrating books and reading, and we've turned the focus of that entirely on to something else.
I feel a bit like if we had a World Football Day and it was decided that the main thing everyone had to do on World Football Day was to write a poem about football. What poem you wrote was the main focus; parents took photos and shared their children's poems and the best poems were celebrated and won prizes. There's nothing wrong with poetry, of course - it's a great thing. And some people like football, some like poetry and some even like football and poetry. But if writing poems about football was the main focus of World Football Day, rather than say actually playing it or watching it, I can't help feeling that conventional football fans would feel justly cheated.
I'd emphasise this is purely a personal opinion. I don't want to 'ban it' or anything ridiculous like that and people are entitled to do whatever they like. For all those who enjoy the way it is now - good luck to you, and have fun. But from this particular book-lover's perspective, you've taken over a celebration of something I love and turned it into something completely different.