[sabellito]

Few years ago I went to a store and paid with my card and 4-digit password. Not 20 minutes later, at another store, I just couldn't remember the password anymore, missed it 3 times and got my card blocked.

I had to make a new card because I couldn't remember the password to unblock it at the bank.

I had that card and password for 3-4 years at that point, wasn't under any stress at all, and nothing like this had ever happened, nor happened again.

[wishfish]

I was worried this would happen to me. I made an entry in my notes app. "Doctor Harry Bottomsmith 801-421-8623 9 am Friday" where 4218 was my PIN.

That's saved me a few times when I blanked out. This note, in theory, will look completely innocuous in case anyone gets access to my notes.

[SenHeng]

I've had a few of these. Until years later when I stumbled upon them again and totally forgot how they were meant to be decoded.

[account42]

You just validated every adventure game player typing in whatever numbers they can find to try and guess passwords.

[kibwen]

This is more generally known as steganography: https://en.wikipedia.org/wiki/Steganography

[ntauthority]

A year ago, I had to go to a bank office and engage in some verification process that also required me to use the physical bank card with its preassigned PIN.

No matter what I tried, I hit the 3-try limit for the day, and opted to have the same preassigned PIN sent by mail to my home address.

When walking back home from the bank branch I realized the mistake I had made: I had entered the correct PIN, but had typed it in calculator/numeric keypad order, and not in phone/PIN pad order.

While I've never used that PIN on a numeric keypad for a PC, somehow my brain associated the numbers with their order on a PC keypad, since I had used my PC keypad to unlock my PC with a PIN numerous times more than I had used any card terminal with a PIN.

So, the next day, I returned to the bank branch office to try the same operation again, and indeed - I had correctly entered the PIN and the online banking transfer limit ended up adjusted just fine.

[SenHeng]

For the past decade and a half, possibly longer, Japanese ATMs have replaced their physical keypads with digital ones where the numbers are randomly placed. Imagine my surprised when the first times I tried to enter my PIN, it kept failing until I took a good close look at the numbers.

[thraxil]

Had the same experience. Went to an ATM one night and the PIN for my card that I'd used several times a week for probably a decade was just... gone. Never before, never since.

[urxvtcd]

I once forgot root password to my FreeBSD installation, I spent a lot of time trying to remember it but failed. So I did a reinstall, and obviously recalled it when prompted to come up with a new one.

[LandR]

This happened to me last year.

Completely out of the blue I forgot my PIN, the PIN I had used every day for years. I was at an ATM trying to withdraw cash, got it wrong twice. It was just gone.

Luckily I cancelled it before the machine ate it, but I had to borrow money from someone to get a taxi home.

I had to request a new PIN and I still can't remember what it was. I now keep my pin in my phone under a contact.

[macintux]

I’ve had the same experience. Walked up to an ATM for the second time in two days and my 4-digit PIN was simply gone from my memory. I never figured out what it was.

That was almost 30 years ago, and thankfully it hasn’t happened again.

[grogenaut]

I use my ATM so infrequently that it's happened to me a few times. I get cash reups selling stuff on Craigslist so I need the ATM like once a year. Luckily my ATM is right next to an in grocery store branch so resetting the pin is 3-5 minutes talking to someone irl

[Vinnl]

I've had this happen to me multiple times, and more often now that so much payment is contactless here (even though I still have the same code as when it wasn't). Additionally, something as simple as a different machine (the most recent instance was a touch screen) can throw me off as well.

[jay_kyburz]

I went for a week holiday and when I came back I couldn't remember the alarm code. Had to call the boss at 7am with the alarm blasting in the background.

[tarsinge]

It has already happened to me blank on the 4-digit PIN I have since more than 5 years. Never thought I could forget something so short I use so often.

[PontifexMinimus]

Some bank cards have allowed you to change the number to a more memorable one.

The other thing you can do is make a mnemonic story to help you remember it.