When you click to create a segment, you get a popup with "compose audience" and "build rule" options, with "compose" being the default pre-checked option.

This makes no sense!
Composed audiences is a limited feature, designed for advanced users, for specific use cases.
I bet if you look at analytics, 99.9% of the users go to "build rule".
I actually thought Adobe would fix this a couple of weeks after "compose audience" being released.
This annoys me and is bad UX with a simple fix.
Please Adobe, make "Build Rule" the default option.