@Dingusberry, lined shirt collars have a layer of fabric between the two layers of shirt fabric which make the collar.
This layer of fabric can either be sewn to the other layers of the collar or additionally the collar can be "ironed" so not only the thread holds the layers of fabric together but also the glue on the interlining fabric, which melts under ironing and joins all three layers together to form a single one.
Lined + fused collars are stiffer than either lined + sewn or entirely unlined collars.
To me unlined collars wear much more comfortable against the skin and because the layers of fabric can move against eachother, no matter how well you iron the collar, it will never lie 100% flat.
I prefer that look because to me it appears more natural, like the rest of the shirt, which of course does not lie flat too.
The same procedures can be down to the cuffs.