It isn't a joke but could be!

[mereman]

I remember going to the BMF (British Motorcyclists Federation) show in Peterborough, on the east of England showground, many years ago.

I parked my bike, after many hours I tried to find my bike...... you know the rest... there was about 3 bike parks and I couldn't remember which I had parked on. So I waited 'til most people had left and finally found the bike.

I was always doing that. One day in Norwich, before all the parking laws, I parked on a side street... and... you guessed it... couldn't remember which one

I guess I won't notice Dementia

[Agrippa]

I was in London on a bit of a pubcrawl and had put my luggage in one of the left luggage places
at one of the main London stations . Later that day I couldn't remember which one it was  and the
ticket didn't state which station it was. I'd been using the tube and travelling about town meeting
various pals . Took me ages to work out where the luggage was, after going to various stations
like Charing Cross, Victoria etc and getting a big Noooo when I handed over the receipt.

[stevieboy]

On two occasions my Tesco clubcard has not scanned at an Asda self-serve checkout. 

[jonclox]

Basingstoke railway station refused to let me through the ticket barrier one day when I was going to Brighton for the day.The railway staff member came and checked my pre-purchased ticket and pointed out that The Caravan Club membership cards don't work for rail travel 
A quick swap of cards and all was well except that I missed my train 

[MattJ]

Basingstoke railway station refused to let me through the ticket barrier one day when I was going to Brighton for the day.The railway staff member came and checked my pre-purchased ticket and pointed out that The Caravan Club membership cards don't work for rail travel 
A quick swap of cards and all was well except that I missed my train 

A few times I have done this, variously with my rail ticket, work pass and front door keys in any of the pertinent locations...

[Malc]

I discovered they cash point machines don't work with a Birmingham libraries card

[Komata]

Malc

Customer loyalty cards tend to engender the  same response if you try to tender them in an opposition' s premises (except that the owners' involved can become  somewhat frosty)...

Using one bank's ATM ('cashpoint') cards in its ATM's ('cashpoint') in another country (yes, that does make sense), can also be easily done, and can have 'interesting' consequences, especially if one is in  hurry and dependent-upon the machine for train fare (with the train's departure being imminent and from a distant platform)...

[Trainfish]

I couldn't find my car in a multi-story car park a few years ago, then realised I was in the wrong car park!

I did exactly the same in Cardiff one time. 2 multi-storeys looked exactly the same but the one I parked in had a tramp sitting next to the ticket machine on the ground level hoping for some spare change so easy to remember which one. He was still there when I went back to collect the car but the car had gone. You've guessed it, the tramp had moved to the other car park! I walked every floor of that damned car park pressing my remote fob and looking for the headlights on a Merc to light up.

[Kipper]

I got a W H Smith gift card for my birthday. Comes as a plastic gift card and attached plastic part the same size. You are meant to separate the two parts, and use the card. Guess which part I took to Smiths, and which part I had chucked in the fire......!

[GScaleBruce]

I stood in the queue in the building society wondering why everyone else's passbook was red, when mine was blue. Fortunately I realised before I got to the head of the queue that I was in the Abbey National when I should have been in the Nationwide...