Someone who runs from indoor location to indoor location due to the fact they're wearing a t-shirt in sub-zero weather.
This is a Canadian phenomenon that tends to occur in spring and fall. Due to uncertainty of the weather and the fact most Canadians like to act immune to cold, The Short Sleeve Hustle is often witnessed.
"Tom is such a dumbass. He didn't even bring a coat."
"Yeah, looks like he'll be doing the short sleeve hustle."
A Short-Sleeved Genius is a person, usually a male, who abuses their minor managerial role within a business setting. This person utilizes their limited power to assert complete authority or assumed knowledge in an aggressive manner. Think a psycho Pep Boys manager or Dwight from The Office. While anyone wearing short sleeves and a tie is a potential Short-Sleeved Genius, it is not a mandatory dress code.
I was at the DMV getting my license renewed when some Short-Sleeved Genius told me I was in the wrong line. He threatened to "write me up" if I didn't change lines. WTF, I don't even work there!