Apple Users

the TouchPad.

For instance, if you touch it with two fingers as opposed to one, it might activate as if you were holding down the command key as well. If you're used to Windows, scrolling will seem upside down, too.

This may have changed, but Macs don't have left and right click by default. You have to hit the command key while clicking the mouse or TouchPad in order to get contextual menus under your mouse click.