At some point in Douglas Adams' Hitchiker's Guide to the Galaxy series, he touches on a unique attribute of humans: the tendency to mindlessly say very obvious things over and over again, as in "You're very tall," or "Sure is snowing out there!" Although the cause of this illogical behavior is unknown, Ford Prefect has formulated a pretty good theory, which is that if humans ever stop chatting this way, their brains will start working.
I have always found this true of myself, and not just in the idle-chitchat way, either. I keep myself busy in many ways to avoid thinking. Left to its leisure, my brain will take me to horrible, horrible places and leave me a shriveled carcass of anxiety. It basically wants to kill me. So throughout the days I keep reading and writing and singing and blasting music and sending emails and planning new hypothetical adventures (going to Portugal! learning to sew! bartending school!) and so forth. It's only late at night, when I lie in the dark in my bed, that my brain has a free moment to work overtime. The result is insomnia, nightmares, or some unspeakable mishmash of the two.
I'm assuming this is true of a lot of people other than me, though others might not be so crippled by it. A blog, after all, is not only something else to busy oneself with, but potentially a good outlet for my brain to relieve itself. Or maybe I'm just bored and want to write some stuff down, but a little tired of writing about the Beatles.