I used to live in the very center of Amsterdam: with one's head out of the window, one could see the red lights.

Two guys who I exchanged mails with (this was in the early 90's, when email was still new to me) but whom I had never met, sort of invited themselves over. Living where I lived, I had loads of students crash at my place so I said OK. One of them was unemployed (or at least he had no money to pay for his stay) so I told him he could crash in my apartment. The other stayed in a nearby hotel.

During the first meeting, the latter guy had to do #2 so he used my rest room. I could hear he had tummy troubles, even though he apparently tried to minimize the sound he produced by sitting on the bowl backward -- so the excrements wouldn't splatter into the water. How do I know, you ask? Well, it's the only way I can explain finding semi-dry diarrhoea stuck to the front rim of the bowl, at the end of the day.

The other one wasn't a much better guest. Trying to be a good host, I let him sleep in my bed, whilst I slept on a mattress on the floor in the next room. At 3am, the clock radio all of a sudden switched on. It woke me up and I hesitated about what to do: it was very loud and yet the guest didn't switch it off. I figured he probably accidentally set the alarm prior to going to sleep, and, startled by the noise, he now couldn't find a way to switch it off.

I was about to knock on the door to offer to help him switch it off, when I heard him moan. I then realized the guy had switched on the radio to overpower the noise he was making, masturbating.

I went back to my mattress and tried hard not to hear anything anymore. The following day I also tried hard not to throw up when I saw the wet spots on my sheets.

100% Disgusting but true story.