An old friend commented that I 'know my stuff' and that puzzled me for a bit. By the time anyone reaches my age, he ir she better know their stuff. Or risk winning the 'Slow Learner' award.
But then I do tend to know things intensively and exhaustively. That is because I develop a near-obsession about new things. I like new things because well... they are new. So I always want to figure out what they are, where they come from, why they are like that and all things related. If I were to create a mind map about what I want to learn about new stuff, the resulting paper required would be knee deep. Metaphorically speaking.
Perhaps I have a psychological condition but I need to know enough about something until I am able to reach a sort of critical mass and I am able to say,"Yes, X is _______ !" And that adjective or noun should be able to describe X to a T.
It took me 15 years to reach critical mass about debate. And what a great 15 years they were....
And yes, in the process, I have gathered tons of 'useless' facts. Yet I treasure each and every one of them.