[mNovak]

I agree it can be super convenient, though 'Sign in with Google' is totally broken for me, because I've accumulated a handful of google accounts.

Every time I log in to a service, I have to guess which account it's associated with (bearing in mind I may have signed up years ago). And if I'm wrong, half the time it immediately attempts to create a new account, and then I'm stuck with a bunch of empty dummy accounts on various services.