Wall Street Journal talks about Steve Jobs' dislike for buttons:
The new Apple cellphone famously does without the keypads that adorn its rivals. Instead, it offers a touch-sensing screen for making phone calls and tapping out emails. The resulting look is one of the sparest ever for Apple, a company known for minimalist gadgets. While many technology companies load their products up with buttons, Mr. Jobs treats them as blemishes that add complexity to electronics products and hinder their clean aesthetics.
Buttons have long been a hot-button issue for Apple's CEO. Bruce Tognazzini, a former user-interface expert at Apple who joined the company in 1978, says Mr. Jobs was adamant that the keyboard for the original Macintosh not include "up," "down," "right" and "left" keys that allow users to move the cursor around their computer screens, giving it a sleeker appearance than other personal computers have. Mr. Jobs's reasoning, says Mr. Tognazzini: Omitting the cursor keys would force independent software developers to create programs that used the Mac's mouse -- a novel technology at the time.