I believe a defining characteristic one must possess to enter the academic world is a certain type of organisational insanity. It's not the sort that's necessarily socially noticeable (although in some cases, like maths professors walking around with a trout tied to their hats, it definitely is hard to miss), but rather of the sort that pops up in conversation. To word it more precisely, I believe it is the ability to be lost in a tangent, be it conversational or conceptual (as applied to vestimentary taste, in the case of the fish-donning mathematician), and to actually forget how one got there in the first place.
I'd like to clarify that I am not just positing this for kicks: it is a thesis derived from empirical observation (try it yourself: you just need to have a 40+ minute conversation with a professor). Furthermore, it seems to increase with age (I assume this is because it is a decay which begins the day one gets one's PhD/DPhil, and things go downhill from there).
Perhaps there is some evolutionary justification for the maintenance society provides for this ever-continuing loop of folly, from thesis to teaching to training the tangential tricksters of tomorrow (couldn't resist)... Perhaps there is something you can only find, you can only discover while on a tangent...
This may seem a spurious claim to you, but if so: you obviously haven't had the (dis)pleasure of going through Wittgenstein's Philosophical Investigations. A word of warning if you do decide to walk down this path, though: Remember to change the trout ever so often.