The new version of Acrobat Reader
I really don't like the new Acrobat Reader user interface.
The Reader is a simple program, so why complicate things by moving menus around etc (and then not allowing them to be moved back)
The traditional interface has remained largely unchanged for 25+ years, so why change it now?
If Adobe really think Acrobat needs a new interface, then please keep the old one handy. I've already changed mine back to the orginal.