Air Conditioning

Why is it that in the summer, when it's effing hot outside, businesses insist on setting the AC so low? Every time I leave the house, it's ninety degrees outside (maybe more). So, I make sure to wear pants and grab a sweater, because it's sure to be freezing wherever I go. I'm having lunch on another scorching summer day, and can barely feel my numb fingers it's so cold in this restaurant. I am wearing jeans and a wool sweater. I work for an environmental group that specializes in energy security, and our office is always FREEZING. Given the current state of our energy security (that is, seriously not secure), can someone tell me what the rationale for this is?