[*for UK readers, please substitute "trousers" for "pants" throughout. Or just giggle, I don't care.]
1. Drawing your pants legs back from someone in disgust as you pass them is insufficiently scornful.
2. Studies have shown that wearing skirts is 90% effective in preventing VPL (visible panty line).
3. Ditto for "plumber's butt," "whale tail," and "camel toe."
4. Ruffles on a skirt can be over-the-top glamorous. Ruffles on pants are only acceptable if your name is Mary, and a little lamb follows you everywhere you go.
5. It is impossible to smuggle someone in — or out — of prison, a masked ball, a hotel room, etc. by hiding them under your pants. (Plus, there is no such thing as "hooppants."
6. When you strap a gun to your thigh in pants, you lose the element of surprise.
7. You don't have to have skirts hemmed differently for flats or heels.
8. Twirling in a pair of pants results in 87% less happiness.
9. The word "skirt" has both a singular and a plural form, usable by all ("I am wearing a skirt today." "Instantly Mrs. Bagnet put some pins into her mouth, and began pinning up her skirts all round, a little higher than the level of her grey cloak.") The word "pants" has a singular than can only be used by fashion-industry people ("Designers are showing a high-waisted, wide-legged pant for fall").
10. Skirt blowing up, revealing underthings? Sexy. Pants falling down, revealing underthings? Humiliating.
[Pattern from MOMSPatterns.]