This was a few years ago and I still think WTAF
I was on a site, a forum type place with occasional meet ups in my area.
I had seen this man there and we had talked anyway he messaged me and we started chatting. I made it very clear I was only after friendship, I knew he was "older" but not how old.
He asked to meet up, I was free and thought yeah ok why not? (WHY?! Oh why did I think that)
Any way we met up, and he said let's go back to his for a drink as it was a bit cold out.
So we walk to his (much further than he said- I was wearing heels)
He proceeds to take me to his flat, which is in some kind of OAPs complex, he makes me a hot chocolate with squirty cream and marshmallows and is treating me a bit like a child. He then said he wanted to show me something in his bedroom. It's a four poster bed with fairy lights all on the top. He says lay down, it looks better. So I did (see, this is really a WTF was I thinking story) and as I'm laying there, feeling very uncomfortable I notice a load of bandage equipment on the back of his door 
I very quickly made my excuses and left.
On my way home I was just wondering WTF had happened and how the fuck did I get myself into such a strange (and dangerous) situation.
Oh and it turned out he was in his late 70s
Oh and he had legally changed his name to a well known character, thing along the lines of 'Dumbledore'