I honestly kind of hate most of Google’s products. While they are incredibly reliable, they often have inconsistent and poor UX, and are liable to either cancel or change the entire UI on a whim.
Redesigned Gmail is ludicrously slow and glitchy in so many ways that old-Gmail was not. According to about:performance, not only is it consistently the most demanding tab in terms of CPU (usually by a wide margin), but it also uses nearly double the memory of Youtube, which is itself also much more bloated than it used to be.
Google is supposed to hire the best and brightest engineers around, yet apparently they require 60-120 megabytes of RAM just to show a couple of lines of text on the screen. It's absolutely pathetic.
That's just what the modern web is like now, chickenshit minimalism, oodles of whitespace, vapid hero banners, plenty of grey Helvetica ultralight on white and a pile of bloat.
I stopped using the gmail interface years ago; it’s now only an imap/smtp server pair for me. The constant changes and moving features just made it markedly inferior to even Mail.app in the long run.
Something that stands out as representing the bad UI as a whole is this ridiculous menu under the upload button on YouTube. A vague, textless icon that you're supposed to guess means upload which is completely pointless when the two sub-items could have just been put into all that wasted space to the left of it.
My company recently switched us to G Suite, and personally I quite like most of the products.
However, helping colleagues with the transition made very apparent that Google tools have many UI inconsistencies. They seem small but actually made the tools quite confusing to many colleagues.
The main issue was the overuse of the "3 dots" icons for a menu. Gmail in particular puts it in several locations for different menus, but in general it's all over G Suite. And there were also many small inconsistencies between products; for example the Gmail settings need to be saved at the bottom, while the Calendar settings autosave. Or in Gmail the settings for "display density" and "configure inbox" are outside of the rest of the settings.