Yeah, yeah, we all hate wearing a jacket in hot weather; it's sweaty and stifling. We might not achieve that super-cool, sleeveless farmer tan, or get skin cancer. (Detect a hint of sarcasm?) Try wearing a ventilated jacket to keep cool. Your elbows will stand a chance against being skinned to the bone, and that skull-and-beer-belch tattoo will stay fresh and pretty on your still-hairy arms. But hey, if you want to look like an armadillo, then by all means rock that vest! And look forward to a few months of painful skin grafts in the hospital's burn ward.