I had a customer pay me £100 for gutters and windows cleaned, 2 weeks later she transferred me the same payment.
When I informed her she had paid twice she insisted that she hadn't paid already lol
I told her to check her online banking, which she then realised she had already paid but had no recollection of doing it!
She isn't old enough for dementia, only In her 40s, must be early menopause I reckons.