One thing would be that with Chrome I can login with my username and password, and I get all my extensions synced the first time I install it or I'm on a friend's computer, while with Firefox I have to wait for their confirmation email, click on it, then wait for it to sync.

You might argue that Firefox's approach is more secure, but every single website in existence is fine with my username and password—including online banking—and I think Firefox is the only software that make me do that extra step.

It's the little things, Firefox just seems to not care about my time. Too many buttons that I'm supposed to hide myself while they should've known no one uses them, too many steps to get to that setting, etc. etc.