Gmail was so groundbreaking when it first came out in 2004. AJAX was barely a thing, and Gmail used it in spades everywhere. I remember it being mindblowing when you didn't have to wait for full page refreshes for simple actions.

My problem is that it's remained frozen in time for years. Yeah, they tweak the visual design every few years. But so many other email clients have far surpassed it, and they've done nothing. Other than create Google Inbox. Which was amazing. And then Google shut it down. ️