conversational math

Flip enough coins, and eventually the pattern will settle into a 50/50 split between heads and tails, right?
Does the law of averages apply to conversation? For instance, if I talk for a long enough time, will there be a point where what I say is interesting or funny no less than half the time?
But then how do we categorize those people who seem to have an abundance one way or the other?
Related question: Where is the fine line between tedious and hilarious? Is it in the delivery, the ability to twist a story, or is it more a matter of knowing your audience?
I know this makes absolutely no sense. How can one apply math to conversation? Maybe it's a notion borne more out of the idea of time; the 7-minute lull, or the point at which a story or joke goes on too long and the point is lost. Or the speed at which gossip travels (Juiciness x people who know = distance).
Or maybe I'm just hoping that years of being boring will balance out in the end.