It keeps us, for one. As for what other things it does... I have yet to live through any of its famed tricks myself, so anything I were to tell you would be second-hand information the accuracy of which I cannot vouch for. It might be better to leave that part for someone else to explain.
But, for what it's worth, that would be close to three weeks now with no noticeable strange happening. If anything, it has been peaceful.