But please. just stop making everything flat ffs. On the GUIs of old, you knew straight away what you could interact with, while now, everything is so flat or hidden away that everything blends together, I have no idea what I can click on and what's static unless I used the app before.
Best example, compare Windows 95/2000/XP to 8/10.
Also, please stop with the auto-hiding bs. Sometimes I have to do a brute force sweep of the GUI with the cursor to trigger some elements to pop up from where they were hiding. WTF?! This would have made more sense 20-30 years ago when displays were running at 640x480 so real estate was precious, but now FullHD is the entry level norm.