Just step back a moment and consider the overbearing and unnecessary nature of this anal-retentive concept.   

I guess the motivation for it is that people are careless with their usernames and passwords, writing them down and having them saved on their devices.   

Why do people write their usernames and passwords down and have them saved on their devices?   
   → because they have so many of them
   → because they are forced to make them cryptic

So, the privacy and security people keep raising the bar for everyone because some of us are just plain stupid.   

Enter Two Factor Authentication.   

Now, if you are entering a domain belonging to a company where you can access company resources and data, there may be some reason to make that entry difficult.   

However, if you are logging in to your account, which is restricted by system software, why would you need to two factor authenticate to your own data?   

There is no justification for that requirement.   It is simply an example of monkey-see, monkey-do in the software industry.   

Two most perverse deployment of Two Factor Authentication that I have encountered was with Verizon.   

I recently switched services from Verizon to MintMobile.   After a few weeks I determined to switch back to Verizon.   

To make a long story short, in the process of the switch, my phone became deactivated despite the fact it had a Verizon sim in it.   When I would try to log in to the Verizon web site, their software would send a verification code to the inactive .   

The result was that I could never complete login to their site so that I could activate the phone!   

Just to make it clear, I was trying to log in to my account to activate my phone but could not log in without my phone being active.   

Thank you, software geniuses.   

Having worked as a systems and software developer for over thirty years, I amazed that there is no usability testing by these mega-corporations.