I have a hard time telling which elements are clickable, and which are not, with material design. Flat buttons , of course, are similar to labels.
Even worse, both Chrome and Firefox have been building Material Design style animation in to the browser rendering, and I haven't figured out if there is a way to turn it off. Even on my own sites, where I don't want any animation, the pages are rendered with unpredictable animation.
Designers seem to not realize that the human brain is fantastic at doing visuals diffs. We don't need animation hints anywhere near as much as they seem to realize and in many cases will actually undermine the brain, like when the change is to slow for the brain to register it.
That web design seems explicitly designed to make your normal way of looking at things fail is not a bug. Also I bet those designers judge themselves (and get performance evaluated) based on how long people look at those sites.