Sigh
People hating on "flat UI" just feels a bit frustrating because it does not really have to be that bad...
But nah, if it does not have bezels and chunky borders, it's bad? x.x
We have enough screen real estate to not need it as much. Make content separate itself with spacing, which you have enough to do that, usually
And even then, high contrast borders can be pretty good, and separating different blocks of UI with color.
...just please don't say that the only true way to do UI is to slap a bunch bezels that "push out" and so on, while keeping everything so... so very... monochromatic? I mean they work, after a fashion, but if you want to recognize what is content and what is the surrounding UI, you have to mostly orient on the bezels while the color ends up almost matching the content. Which feels rather tiring x.x
Dunno, just some thoughts