1.) Because all the people that need something are working while all the people that can approve things are on month long vacations.
2.) I know everything is global now, but seriously, for a mostly US based company doing business in the last 2 weeks of December or the first two weeks of January is a waste of time.
3.) #2 does not apply to retail. If you are in retail, then may god have mercy on your soul during November/December/January
4.) Work stress + Holiday stress = Your Mugshot on CNN Headline News
5.) Who the hell in their right mind starts someone on a new job during this period when half the month is taken up by office parties and vacations?