I know I'll get some flames for this one, but it doesn't matter because the open-source sendmail daemon you'll be flaming me on is broken. When we tried to upgrade it, everything else broke. You can tout open-source solutions all you want, but I'll take a functional out-of-the-box solution any day. I don't have to know as much, and if it breaks I can get technical support.
Mind you, I'm not the one managing our servers. This is a good thing. I get to focus on creating Schlock Mercenary, and writing open letters full of irrationally sweeping generalizations that probably irritate the concatenated grep out of the rabidly loyal Torvaldniks. And in the same breath I can lambast the likes of Microsoft whose anticompetitive practices have turned words like "open standards" into epithetiotomiable streaks of choice vulgarity.
I can also make up words like epithetiotomiable, which means "able to have an epithetiotomy." Or words like "epethetiotomy" which means "the act of surgically removing one or more epithets from a vulgar phrase." Hah! Grep that, you phreaks.