Favorite UI system in XIV

This may be a very minor thing, but needs to be mentioned, I love, love, that there is a toggle for having headgear shown or invisible on your avatar. Helmets never seem to look right on my character at all, and when I found out you can have headgear on, but keep it invisible, I about had a heart attack because that was something I really wanted back in my XI days.

My Elvaan DRK was the same style Elvaan as my Elezen, and being in the DRK armor without the helmet on, looked far more bad ass than with.

What's your favorite thing about XIV's UI?

Funnily enough, 'hide headgear' was later retroactively added to FFXI as well after it was added to FFXIV 1.0. ;)

Technically it's not so much part of the UI and just a gameplay feature, but I love being able to dye gear and use glamour to change gears' appearances - no more stuck wearing a butt-ugly piece of equipment simply because it has good stats. ;)