The Mac still ships with a one-button mouse. This made sense to me back in the System-6-and-earlier days. Other operating systems had confusing and inconsistent uses for their multiple mouse buttons, and Apple's solution seemed to be the simple and elegant one. Apple's one-button mouse was easier to use, and also of much better quality than the cheap multi-button mice that were shipped with PCs back then.
Things are different now. Other operating systems introduced the right-click context menu; Apple responded by using a Control-click. This has become clumsy. The context menus have become the primary means of controlling a lot of on-screen objects, yet Apple insists on this two-handed method. It's too bad, because I really like the look and feel of the Apple Bluetooth mouse; I just want another button (and maybe a scroll wheel).
I know I could just take the easy way out and buy a third-party multi-button mouse, but as an experiment I am going to stick with the one-button mouse. Maybe I'll get used to it. Maybe I'll develop carpal tunnel syndrome. I just want to see if maybe Apple's UI designers are on to something. (Although I wouldn't be surprised if all Apple's UI gurus have multi-button mice.)
All this use of the Command, Option, Control, and Shift keys along with the mouse, as well as my increasing use of keyboard shortcuts to avoid the mouse, has made me start thinking about exactly where I should put my fingers on those keys. When I took typing class back in high school, I learned to use my right thumb on the spacebar and my pinky on the Shift key, but they didn't have these extra keys back then. I've been sloppy, just hitting keys with whatever finger happened to be closest, but I think I may be more efficient and less likely to suffer from RSI if I can touch-type the modifiers like I do the rest of the keyboard.
Should I press Command with my thumb, my index finger, or my middle finger? Should I press Control with my pinky, or with my ring finger? When I use a shortcut like Command-Q, should hit both Command and Q with my left thumb and middle finger (which is the habit I've developed), or should I hit Command with my right hand and Q with my left (thus avoiding a weird stretch of the hand)?
I've decided, for now, to try to consistently use my thumbs on the Command keys, index finger on Option, and ring finger on Control or Shift (and if I have to hit both Control and Shift, use index on Control and ring on Shift). I am used to using my thumb for Command, so I think this will be an easy habit to develop.
The harder challenge will be to break my habit of one-handed "chording"for Cmd-Q, Cmd-Tab, Cmd-S, and other common shortcuts that are possible with the left hand. When I use the Shift key, I have no problem using two hands, so I hope I can develop the same habit for Command.
Maybe I should just buy a new mouse.