Left-handedness
Things that are designed by right-handed people can cause problems for left-handed ones. These include guns, cameras, screws and in recent years the computer mouse and the iPhone. Many objects are sold in left-handed versions, which are often more expensive than the right-handed versions. Some items such as a computer mouse can be designed for right handed people but still be used by left handed people and in some cases may even be an improvement for right handed users.