Yeah, me too. And its amusingly frustrating to watch. And we know why double-clicking is a thing, and why it's not consistent across widgets, but I wonder if we'd be better off if the mouse originated not with "left" and "right" buttons, but instead "do" and "select" buttons. The Do button would open the files and visit the hyperlinks, the Select button would add the object you're looking at to a stack of selections, or provide more information about the thing you're pointing at, or some other lower-cost action.
(I just changed the setting on my desktop to use single-click-to-open, and was immediately punished by it. Couldn't merely select files anymore without fear :) )
Middle button (usually) on a three button mouse: Activate a menu to invoke an action concerting the contents of a window; e.g. carrying out an editing operation on text withing the window. (...)"
Right button on a three button mouse: Activate the menu or invoke an action concering the manipulation of the window (view / Morph) itself; e.g. moving or closing a window.
Shouldn't you also have a third button to list available actions, or would you throw that away? Overloading the select button would be just as confusing; I hope you don't want to do that.
You're right of course. At some point a trade off has to be made among usability, discover-ability, and simplicity. (Pick any two).
Adding another button reduces simplicity, but enhances the other two. Apple's one-button mouse—at the other extreme—makes things simple and discoverable, but often not as useable as I'd like. I still don't know how OSX's equivalent to Windows' [Alt] key access to menu items (does it exist?)
I do think using three buttons are good -- I'm not so happy with the classic "Xerox Parc/Smalltalk" layout -- I'd prefer to have a button on the thumb (like many logitech mice have) and a scroll-wheel in the middle that's not a button.
Which leaves us with a bit of a problem for touch screens. While it might be ok to demand users to learn one and two-finger touch -- three finger touch might be going a bit too far...
I used to use an MX Revolution mouse[1] that had what you describe. Multiple thumb buttons, that amazing flywheel scroll wheel, that other thumb wheel. I loved that mouse.
Unfortunately I love trackballs more than mice now, and am severely limited in my choices. The Trackman is nice, and has a couple of extra buttons, but it would be so nice to have something close to what I had with that Revolution mouse.
In response to your comment above, no I wasn't being ironic :). I'm sure I've seen similar schemes before that informed my "idea", though.
(I just changed the setting on my desktop to use single-click-to-open, and was immediately punished by it. Couldn't merely select files anymore without fear :) )