You can legitimately complain if the other guy wins.

Because you want to wait in line in a weird building near you and encounter some slow-moving people as you catch up on your reading.

You can brag about it on Facebook/Twitter.

People are less likely to think you're a lazy, uninvolved jerk.

You'll be one less vote that keeps the election dragging late thereby making everyone stay up past their bedtimes and be cranky tomorrow.

You might get a sticker.