House keys are a minimal inconvenience because the lock on your front door also affords minimal security. Just ask the Lock Picking Lawyer how long it would take a determined intruder to get into your home, whether by picking, force, or finding a weakness such as open window.
If your home had high security, I can guarantee that you'd feel the inconvenience.
A password, in theory, could work the same way. Except that the normal password UX involves people remembering the password, which entails a huge security compromise.
Yep, I'd call that a significant inconvenience (for a home that someone like me lives in).
MFA irritates me because usually it isn't my choice.
Part of it consists in the incredibly varied ways it can manifest. I could receive an SMS code, an email code, I could generate a TOTP code (choice of two Yubikeys), I could use U2F/FIDO (choice of 3 Yubikeys), I could get a Magic Link, I could use Sign in with Google, I could punt and use a code on my emergency backup paper. Don't forget to pass a CAPTCHA, and your password probably expired while you were away, as well.
Of course this all transpires after I've unlocked my password manager's vault, which has its own style of 2FA security, its own timeouts, and its own UI/UX quirks.
So you can see the sheer dizzying possible mutations of the MFA flow. Sometimes you don't even know what they'll hit you with until you try to log in!
What amuses me is "We sent a code to your email. This message will self-destruct in 10 minutes." when email used to arrive on the scale of 5-7 days if the server was overloaded or busy. Oftentimes I find myself racing multiple timeouts to run the gauntlet of MFA in whatever way has been mandated.
— Frankmin Benjalin