1. Ah, nature
A Northern Arizonan might get stranded hiking on the San Francisco Peaks and need a mega-bucks Search and Rescue bail-out; a Southern Arizonan has definitely shot a saguaro cactus only to have it fall on him, impale him, and kill him.
2. Shorts
A Northern Arizonan wears tights, socks, and river sandals with his/her shorts in the winter; a Southern Arizonan wears shorts, flip-flops, and a tank top all year round — even when visiting Flagstaff in January.