The many hazards involved in its quest and clearing the Divine Beast itself, combined with the long lead-up, make it the most annoying one to deal with. It's not even just that it is bad, it's also because the other ones are much better and easier than it. Vah Rudania is the worst Divine Beast for a few different reasons. Related: BOTW 2's Delay Is Actually A Good Thing During the Great Calamity, Ganon seized control of them and slew the champions inside, leaving Hyrule virtually defenseless against his forces as well as the Guardians that he also bent to his will. BOTW didn't truly show the Divine Beasts' terrifying might, using them only as dungeons for Link to crawl through, but Hyrule Warriors: Age of Calamity let players carve through massive hordes of enemies with them, driving home just how strong they really are. They were made 10,000 years prior to the start of the game by the ancient Sheikah to be engines of war, designed to combat Calamity Ganon, but were sealed away by the then-king of Hyrule, who feared their immense power.
The Divine Beasts in Breath of the Wild are massive machines that mimic real-life animals.