Recently played Signalis (highly recommend if you enjoy survival and cosmic horror), and I just have to laugh at myself for a second because I truly solved a puzzle based on nothing but Aigis.

There was a butterfly room with a safe that had a four-letter word as the combination. Because another room early-on had a blue butterfly, I'd been in Persona Mentality, and the current area had a Tarot-themed puzzle, so I thought "Haha Aigis is associated with butterflies, and her arcana is Aeon, so what if--"

and yeah, Aeon was the answer to the butterfly room.