I've been with my bank since I was 18. I'm 34 next week.
Does anyone remember a few years ago when Martin money saving expert was telling everybody to reclaim bank charges? I wanted to do it so I requested all my bank statements form when I started the account, I had to pay a tenner or something like that and even though I never reclaimed the charges it was till worth it because it was like reading my biography.
Remembered some really crazy nights just from the location of a cash machine. It was a fascinating read, I thoroughly recommend it if you can cope with seeing how much money you've wasted over the years.
It's probably more interesting/useful for people around my age who had a life before social media, but I think it's even more revealing than looking back over your social media feeds anyway.
If anyone's ever thinking of writing about their life it would be really good place to start.