Great question!
Popups are becoming a very annoying thing, and every time one appears, people look for where to cancel it.
I see also many Odoo users looking for the cancel button before reading the often important messages that appear in a popup, such as whether to create a backorder or not.
Even better is Ermin's comment, saying that no software working like this, proves that it is time to innovate, and improve the UX!
Odoo is already doing a lot, a good exemple are the color distinctions in several "status" situations, in the last versions.
It is time to differentiate how to present questions where the user has to take decisions from error/exception messages which the user doesn't understand (and doesn't want to) and would simply like to have a button to send it to the system administrator.

Popups' days are over!