I had this with a colleague and, before I'd even stopped talking with my sentence, she'd started gearing up her response with "So...", it infuriated me no end.
In my experience it doesn't seemingly correlate with intelligence either, I've known quite a few people adopt it. I always thought it was anxiety related.
So there's my take on it, anyway.
Prefacing a sentence with "Basically" is much more criminal, IMHO.