Fashion or Function?

I've heard all kinds of theories. Everything from... "There are only two kinds of tails, pin tails and square tails... everything else is cosmetic," to... "Everything matters."

I have a theory of my own, but I'd like to know what everybody here thinks.

Can you feel the subtle difference between a thumb and a rounded pin? A square and a squash? A swallow and a round tail? I'd like to know what you can FEEL... not what you've heard.

Weigh in...