"Curses!!"

Why is it that whenever someone yells something like "curseeees!!" or "I'll get youuuuuu!", they shake their fist at the sky with unrelenting fervor?

Upon learning of my own viral sickness, I proceeded to yell and shake my clenched hand upward. I then realized that it is only through modern society and severe cliché that I ever learned such an action. Why upward, towards heaven? Are we blaming God for our own failure, or are we just attempting to create a telepathic communication with the problem without shaking our fist directly outward, and possibly offending a passerby?

I have thought of many a possible reason, and have concluded to reform my own actions. I will now shake my fist at the source of my grievances: The demonic entities that elicit my sickness, aka my own inability to stay healthy.