System Preferences -> Keyboard & Mouse
Check "Tap trackpad using two fingers for secondary click".
Much faster and more comfortable than moving to a physical button.
And, as hard as it is to believe, there are a LOT of computer uses who have difficulty even using one button (or, just don't WANT to know what right-click does). I have, over the years, worked with a few myself, and it has nothing to do with their intelligence (a couple of them are MENSA members).
edit: btw, iMacs and Mac Pros ship with the MightyMouse. The default configuration is a single "button", however it has 4. (left, center, right, and side-buttons).
(also ignoring the attempted insult of the OP. Especially "enjoyed" the zero effort which was put forth researching the topic.)
edit: guess I didn't ignore it that well