PIN numbers

What's the deal with people not knowing their pins? I see it most often with people who use tap to pay.

They'll say stuff like: "why's it asking for a pin?" "This card doesn't have a pin" "can I bypass the pin with tap to pay?" "Nowhere else asks me for a pin" "well what do you want me to do? I don't have a pin"

What I want to say is "you are using a debit card, of course it has a pin. You're just either too stupid to know your own pin, or it's not your card" but what I have to say is "wow that's weird I don't know why that would happen".