Imponderable question #2

Biologically, its because you can only get goosebumps were you have a hair follicle. Inside the hair follicle there is a muscle called the Erector Pili muscle that pulls on the hairs and makes them stand up--this is what we call goosebumps. In animals with fur such as cats and dogs these muscles make their fur stand up which does two things. 1) it allows their fur to trap air between it and the skin, making a air cushion that can then be warmed and used to keep the animal warm. 2) it can make the animal seem larger which can help the animal avoid attacks. Unfortunately (or fortunately depending on how you look at it) we do not have that fur so we get neither function. It is though to be an evolutionary hold-over.

sometimes I do, lol :)