Against the experience of SPAs

Some things you have to consider with SPAs:

What happens when users refresh the page?
What happens when users click the back button?
What happens when users click the back button twice?
What happens when users click the back button twice, the forward button once, and then the back button again?
What happens when users try to open a link in a new tab?
What happens when users users copy the link from the address bar and send it to a friend?
Where does the page focus go when it navigates?

But SPAs make sense in some cases though.