When untreated, all caps text creates problematic spaces between letters. Tracking fixes it mostly for web and app design, kerning fine-tunes it.

Knowing what broad genres of typefaces exist and what feelings they evoke, can be a handy tool to dig through the tons of available fonts out there.

What should you pay attention to when choosing a font for your user interface or app?

Every minute when the time is changing all numbers shift around and this just annoys me.