Realising you're going crazy is actually a sign that you're not all that crazy. Yet.
Of course, not realising you're going crazy is a sure sign you're going crazy.
How many times have PCs realised that they're going crazy?
Luke: ... Okay, that was embarrassing.
Yoda: Fortunately, quick on the uptake, on the Path to the Light Side, is not.
Luke: Right. So Vader has the Lost Orb, and she's on the new Peace Moon. Which is... where exactly?
Yoda: Know that we do not.
Luke: Who's "we"?
Yoda: You... me... this rock...
Luke: Riiiight, okay, so...
Luke: I'm just going to go over to the Midi-chlorian Tree for a while, and...
Luke: Great. I'm the one talking to trees now.
Yoda: Your first step on the Path to the Crazy Side, you have taken! Ah ha ha ha!
Yoda: Also, talked to Lord Elric Fluffypants already, I have.