It'd drive me crazy if Gmail _didn't_ do that. Love the keyboard shortcuts, including and especially the ones that override. Highly productive compared to the alternative.
I dunno; I really preferred the alternative I used to have: reading email in a proper email client. The only reason I use the web client now is that it's easier when I'm also using my phone to read mail away from my computer. And I'm strongly considering just returning to desktop-only email; that's how much I miss reading mail in gnus.
And I think there was some trouble with IMAP at the time too, so the path of least resistance was to just use the web client on my desktop. But, as I noted, I'm thinking of going back.