I have mentioned this before , my mates missus got one the other lads to dj at a surprise birthday party for him ,big marquee in the back garden , blah blah blah , he did three hours of tunes using the birthday boys collection , b-sides , underplayed , etc ....
The birthday boy thanked him and commented on a blinding set of records and could he write a few down that he'd played ,
To say he was gobsmacked was an understatement when he realised the tunes were all his already !!
You never know your own collection that well