The pony world

Discord's rebellion against Equestria in "Twilight's Kingdom" was actually planned by Princess Celestia from the beginning, so that the secrets of The Harmony Box could be discovered.

The episode "Daring Don't" was a fictional Daring Do story, not actual events in Equestria.

Derpy Hooves is the smartest Pegasi in Equestria. She was sent undercover to Ponyville by Princess Luna and Princess Celestia.

Princess Celestia and Princess Luna unleashed the Windigos upon Equestria to prevent Ponies from warring.

A lot of Equestria's history is not known to most Ponies. Princess Celestia only talks about it when she is asked or thinks it's relevant for the present.