I thought that it was just "proper" or more respectful to always use your right hand when shaking hands. Is it just because there's so many right handed people?
interesting, I never knew that shaking with the left was wrong. But yes, I have heard that there are more righties that lefties, but I don't understand that (isn't it just a 50/50?).
About 90% of people are right handed. In America and most westernized countries, it’s not rude to shake hands with your left hand, just less common. I do believe there are some countries/cultures, particularly in parts of Asia, where it is considered rude, but I’m not 100% sure on that