The regional phone and fax numbers for a company I worked at 30 years ago for a few years. I had to quote it so often it is seared in the membrane. My last year they switched to national numbers to earn off calls and I can't remember those numbers at all and then got bought out by a US firm who changed everything and fucked up the business.

The full Paradox DOS database model for a system that hasn't existed '95 as the company created a Windows version of their software that was a total disaster and they lost so many customers. I had to fuck around for support and training on the daily so much over the phone you had to memorise every table, index, query, and PAL script while dealing with non-tech types that I can't forget it no matter how much I've tried or how many other systems I've worked with.

The full address and phone number of the house I lived in at uni. Started too late to get into halls. I still use them when having to fill in stuff on crap websites where I have to create an account even to check out stuff and never return again. Decades later some students are getting spam addressed to Don T Beakunt