It probably has to do with the fact that I work a 40 hour week, every week, 52 weeks a year. Never take any days off, never call off sick. I think that breaks the little withholding formula when you do that.
I haven't called in sick in 7 years. I unfortunately don't get any vacation days or holidays either.
Man, I need to find a new job, if I got holidays off, 10 vacation days, and 5 sick days like NORMAL people then I would be working 20 less days per year.