If Yellowstone went off at this point in time (which is likely due to it being overdue for an eruption) civilization would collapse, and humans would like cause a mass extinction by starting wars over dwinling resources (food mostly) that would be very rare due to the ash cloud blocking sunlight and preventing growing seasons. It would also be liable to start another Ice Age.
My thoughts on it are as follows: what do I care? I can't stop the volcano from erupting, so why worry about it? When it happens, it happens, and we get to see something no creature/plant alive today has seen before (dead creatures/plants excluded). I'll just enjoy myself until it happens