Canonically, a Pokemon's hidden ability is related to what it's dreaming about and what it wants. Let's have a thread to discuss hidden abilities and why some Pokemon have the ones they do, just for fun.

>Corviknight (Mirror Armor)
It's dreaming about grooming and polishing it's armored body.
>Hatterene (Magic Bounce)
It's worth noting that the original Japanese name for it's HA is "Magic Mirror". Hatterene wants to be able to reflect all those emotions back at the creatures around it, so they can be at peace.
>Tangrowth (Regenerator)
It's dreams involve it's vines growing faster than before
>Centiskorch (Flame Body)
It's dreaming about cooking it's food
>Omastar (Weak Armor)
It dreams of not being weighed down by it's shell; due to that being what caused it to go extinct in the first place
>Blissey (Healer)
No matter where it is, Blissey is happiest when it's helping to take care of someone else
>Gallade (Justified)
Even in it's dreams it's still battling the forces of evil
>Gardevoir (Telepathy)
It wishes it was able to talk to humans