I often notice that people who have open reel decks and/or tube equipment are nicest

They have to be nice because dealing with all the reel to reel frustration and lack of available things to listen requires a certain amount of tolerable skill. and Dealing with people as we know is incredibly challenging.

I suppose tubes and warmth go hand in hand. I also think tubes and reel to reel decks say a lot about one's level of curiosity. So many tubes, so many functions, so many voicings, so many designs. Reel to reels, so much mechanical complexity and it's right there to see, not some magical unseen technology like digital and streaming (although I love these as well, all in service to the music). 

The patience and meticulous attention required for reel to reel probably would make for a calm, friendly, and controlled personality.  Does this make such owners also more inclined to be serial killers?

Yes, warmth, and palpability.

@larryi  Most probably, never ever stop by the creepy reel to reel dude's house to buy any gear. He'll probably have it priced low to attract dozens of suckers. When you do show up, he might just boil you in his serial boiling cauldron along with the other audio nerds who tried to beat you to it.....Danger Danger McGranger...

The patience and meticulous attention required for reel to reel probably would make for a calm, friendly, and controlled personality.  Does this make such owners also more inclined to be serial killers?