You mean the right? I think it's a consequence of people being mostly right handed. It's just easier to reach things to the right over reaching them on the left

You mean the right? I think it's a consequence of people being mostly right handed. It's just easier to reach things to the right over reaching them on the left, for example when sifting through a stack of papers. Similarly on touch screen devices, holding a phone on your right hand means it's easier to reach for a scroll wheel located on the right side of the page opposed to the left one.