All of the above plus the mental aspect. Personally I would rather be out in 90 degree weather hitting it hard with sweat rolling off me than the least bit of cold weather. I am a shorts kind of guy, would wear them year round. When it starts to get cold out I put a cap on, heavy coat, and stick with shorts. When it gets colder than what the jacket can handle I would rather sit inside in shorts than put pants on and go outside. Maybe I need to move further south**********Hawaii maybe.