"same reasons you wear boots, and gloves. Pants offer you a layer of protection that shorts don't, not talking chainsaws here, just basic protection from insects, poison ivy, hazardous materials (gas, diesel, blood born pathogens) splinters, debris, scrapes (skinned knees), the Sun, and it looks more professional. "
Gotta agree to a certain extent, my legs get a little more scratched up while wearing shorts. Some BASIC protection for sure, that I can do without for the comfort i get with shorts.
Comfort is an ergonomic concept, imo. As important as glasses not getting foggy to me.
Some things you said, I gotta disagree. Protection from spilled gas? No. Once you spill gas on your jeans, it soaks in and touches your skin all day. Plus, I don't spill gas. ;>
"looks more profesional"
Good one. I know how to look like a professional, and sweating more doesn't equate with that. Chaps, helmet, required items = professional. Chainsaw pants? Professional. In 90° weather? Not for me. Shorts certainly don't lose me jobs, I promise.