Something I've always loved about Skyrim was something very specific -- a line from the quest The Cure for Madness, in which Cicero, still unseen, shouts through the Dawnstar sanctuary: "could you at least... slow down a bit? I'm not what I used to be."
Even before I really started paying attention to Cicero and loving the character as much as I do, that one line instantly clicked as a double-entendre after having read his journals. The first and most obvious meaning to "I'm not what I used to be," was his age. Cicero is canonically in his 30s-40s by the time we see him in Skyrim, and on a surface level he's talking about how run-down he physically feels. But the second meaning is what's most intriguing. He takes the phrase "I'm not what I used to be" literally, in that the line represents how much he'd changed from his former self throughout the course of worshipping the Night Mother, being alone with her for at least 10 years, and finally arriving in Skyrim and seeing Astrid trying to take a personal hold over the whole Dark Brotherhood.
That line is the first blatant signal to the player character (at that point in the game, the Listener) that Cicero is so much more self aware than he ever openly lets on. And that one line is what fully cemented my love for Cicero just as a whole during my first Skyrim playthrough.
