What aspect of design do you like?

I was asked this question earlier this week. Sadly I was flummoxed and mumbled something about layout! The context was to be fair a meeting where I was surrounded by document design examples. I could have said one of the following. Balance,
Rhythm, Proportion, Dominance and Unity. Or of course colour, line, form. Or life itself. All life is designed, all life is design, design is life. That meeting could have got really interesting.

What is design? What is good design? What is bad design?