V-Necks and Half Turtlenecks? Formal wear?

I don't understand why V-necks shirts are considered to be dressier than a regular shirt. Why does the V make it more stylish? Would a square instead of a V also be dressier than the standard circle/oval?

Also, the half turtleneck...what's with that? Most of the time, it isn't even on a sweater. It is a long sleeve T-shirt with a half turtleneck. And these types of shirts are worn under suit/sports jackets. That, I truly don't understand.

I'm sure this argument can be made against any type of shirt. Why is a shirt with a collar considered dressy? Personally, I think collared shirts look better than non-collared shirts.

I'm not saying I don't own more t-shirts than I should (my drawers are overflowing with them) or that I don't follow t-shirt blogs (I love shirt.woot.com).

So, call me plain or conservative in my fashion sense, but V-necks and half turtlenecks just don't make any sense to me. Am I wrong?