What's the most annoying two-factor authentication method you've used?

users often find SMS OTP to be more inconvenient due to potential delays, dependency on cellular signal, and susceptibility to SIM swapping attacks. Passkeys and hardware security keys are generally considered more secure and less annoying for two-factor authentication.

Not sure but Customer.io has a nightmare of a login process if you're not the account admin.

Time-based authenticators that then trigger you to confirm it is you via email/an additional screen are pretty over the top. Happens to me with Meta occasionally.