My scariest date was with a guy with whom I shared something pretty rare in my online dating experience - mutual chemistry. We met for coffee and seemed to really be connecting. As I was reluctant to suggest dinner at a restaurant because my budget was tight that week, we ended up back at my place for some leftovers.
I heard him make a phone call when I was in the kitchen, but didn't think much of it, until we were making out a bit in the living room. Apparently wanting to lay it all out there, he stopped kissing my neck to tell me that the call he made was to his parole officer. He then proceeded to tell me that he'd just spent a year and a half in prison because he'd tried to strangle his girlfriend. He didn't actually say the words, "I tried to strangle my girlfriend," but that was the inevitable interpretation of a lot of hemming and hawing about a volatile relationship, a fight, and his hands somehow ending up around her neck.
He hastened to assure me that he had had anger management training and that he understood if I wanted to think about whether or not I wanted to see him again. He was sweet about it, actually, and I didn't feel at all threatened by him, but nevertheless I politely saw him out and, I admit, locked the door a bit more hastily than usual.