Why can't I see all the stamps on my Passport?

Sometimes it looks like stamps are missing from the passport - they are there but you have to know the trick.

The background picture of the passport stamps looks like a book so the intuitive thing to do is to click somewhere to turn the page. However, you can see all your stamps, including the 'milestone stamps' (100, 200, 300 miles) by swiping (in the case of phones) or clicking and dragging the stamps across. (in the case of a desktop computer).