Only 7-10 percent of people are left-handed. I am among those 7-10%. Playing DJ Hero at my friend's house, I was having great difficulty scratching the disc (or whatever it's referred to as) since it's built for righties. Luckily, the DJ deck (or whatever it's called) is reversible, and I then had a great time playing the game.
With the advent of the Wii, the DS, and peripheral-based games like Rock Band and DJ Hero, more active approaches to gameplay are more prevalent, the use of one's dominant hand has become more important. Anyway, I'm thankful that developers who have designed their games to work for the righties, as well as the few of us lefties in the world, and for the one's who haven't: shame on you.
That is all.