I love you... BUT...
The original purpose of UGG boots were to be worn on the Beach. Uggs and Emu are Australian beach wear companies. The purpose was something comfy you could put on after surfing and could wear back to the car without getting sand all up in everything. So technically, you hate girls that are wearing them how they are actually meant to be worn.
Also. Purses with long straps are meant to go between the boobs. it usually means the items are heavier and the weight is dispersed better. Or, the purpose of this was so that it's significantly more difficult for someone to steal your purse. on the shoulder, all you do is grab. across the body and you need to get it over their head. As far as small purses with long straps, either way. If you're moving around a ton, it's easier across the body cause they tend to fall off the shoulder. You get a long strap so you have both hands or so you can be less worried about theft. Long chain straps are best if in a place where theft is very common. They legitimately will just cut the strap of your purse to take it and the chain stops that.