User interface design

I am reading about user interface design these days and came across this cool line "Using DOS is like juggling with straight razors. Using a Mac is like shaving with a bowling pin" and I agree with it since I have used both the platforms. I my first class on AutoCAD was on DOS and experience was "I am better off manual drafting." Since we are using software and various programs are creeping in our lives in almost everything so its usability is gonna count.