Till today. What is the right amount of buttons?

It started with 3 Buttons and than 1 for the macintosh, 2 For Amiga, 2 for MS-DOS (ContextMenu).

Often behind the discussion: "Profesionality" vs too simple.

Interesting questions: Were the 16-bit-Homecomputergames differeent on Atari ST/Amiga and on Mac? An how? 

(First Impression: No second button used in 16-Bit-Games.)