When your brain processes this decisions you use energy. In a given day we have energy points. The more you consume them in things that don't matter, the less you will be left with to handle things that matter.
Not just Steve Jobs, even Mark Zuckerberg wears the same t-shirt, a grey t-shirt.
Regardless, your point is solid. Expressing yourself and your happiness should come first. People like Steve Jobs never get a trill from their clothes. What gives them a thrill are the results of their work