Are blue or brown eyes prettier?

Answer 1

This is a matter of opinion, and will vary depending upon where you are at in the world. In Northern Europe, blue eyes are more common so brown may be considered "prettier" because it is rare. The reverse is true in the Americas - brown eyes are much more common than blue, so blue is considered "prettier".

However, I think it has less to do with the color (brown vs blue) than it does with how the eye color contrasts with the rest of the person's features. Blue eyes with dark hair is striking; brown eyes with fair hair is intriguing. Both of these combinations are somewhat rare, since hair and eye color tend to be inherited together (blue eyes with fair hair, brown eyes with dark hair).

Also, to be fair, there are other eye colors that can be beautiful - green, hazel, amber, etc.