Use two fingers to put in your PIN

One actually presses, the other one doesn’t

You could generate an absurd amount of possible PINs that could work on your card, giving any PIN peepers a seriously hard time, should they somehow have the intent to get ahold of your card and PIN through spying and pickpocketing

Safes, doors, etc. same principle

Even better tip: commit your false finger movements to muscle memory so not even a recurring stalker can bypass it

This will be totally overboard, and totally unnecessary, most of the time. But like any kind of security, it’s good to have it even if you hopefully never need it