Me in FE3H not realizing restoring the church statues gives you stat benefits until right before the timeskip.

Metal Gear Rising in a nutshell, didn't know how to parry until AFTER I beat Sam

Me not realizing how to cook in Breath of the Wild until 20 hours in

Me learning about quick turn in RE4

If you duck before the round gates in Harmony of Dissonance you can warp instead of it just taking you to the other castle.

Discovering you can rotate camera when in overworld in SMT IV

When I played Dust: An Elysian Tail I somehow air dashed or something over the entire area where you get the roll ability and beat the game without it When I went to play hard, my friend told me "just roll a lot" and I was like, "how do you roll??" Big discovery ensued

@lythero BotW

Me, trying to review Battle Princess Madeline before the day one patch. 'Pray at statues to earn new weapons' - a piece of vital information, handed to a random NPC in the town.