Just experienced the most hostile MFA login I've seen in a while, from, naturally, a tax accountant (for a nonprofit I'm an officer of).
You get sent a 20 character mixed case code, which is sent to your phone as a image via MMS, in a font suitable for use in difficult CAPTCHAs. You have 3(!) minutes to receive it and enter it correctly or you have to get a new code.
Accountants seem to have singularly bad client login systems.