Credit to Tim Buckley - Ctrl Alt Del

I love it, when Devs anticipate that players might break their levels and reward them for it.

E.g. when I played Supraland, I had it happen several times, that I managed to get to places that were obviously not intended to be reachable - you know the drill: Low poly terrain, low res textures, holes in the terrain, invisible walls everywhere,... You keep exploring that wasteland, carefully managing to not fall of, go around a corner and... There's a chest there waiting for you.

Or some of the coin stacks in Super Mario Odyssey, that you'll never really see or collect, until you do some crazy trick jumps or so to get on top of $building.