I really enjoy graphic design, typography, neat looking things etc,
so I try to focus on aesthetics of tools I make.
I think UI design and how things look are as as important as performance and robustness.
But I'm not super good at it, so I work with a proper designer on my current project.
The feeling of breathing life into designs and making visual stuff work it truly magical.
(But I would not like to program a game. It's hard to explain why =)