I have two. The first we went on a day trip to London (about 2 hours away). We went to my favourite Indian restaurant. The journey home was a nightmare, should have been 2 hours but ended up being 4, with a replacement bus service in the middle. On the bus he started complaining of a stomach ache. There wasn't much either of us could do as obviously there were no toilets on the bus.
When we finally made it to the train station, he was in a pretty bad way and shot off the bus and started bolting back towards his with me following behind. It was about a mile, a mile and a half across the other side of town. He insisted on cutting through the park in the pitch black and I really didn't want to with no lights but went anyway. All of a sudden he disappeared into a bush next to a row of houses near the end of the park. I waited, wondering what on earth he was doing. Then of course I realised
He came back walking a bit strangely and said he'd had a 'reaction' to the food. And took a dump in the park.
I know you can't help it when ahem, shit happens, but we had passed numerous pubs that were open that he could have ducked into! I felt bad for him but I just couldn't shift the ick after that... and yes I did dump him... I think it was the realisation that he couldn't have wiped... 
The second I made a thread about here as I was so stunned, I was alternating between shocked silence and laughing my head off. I've copied and pasted the gist of it rather than type it all out again:
"I've been seeing a guy for about 4 months. He works a 'normal' job and I work from home, freelance, long and anti social hours. It's not uncommon for me to work overnight, sleep pattern all over the place etc. I've had to put my foot down before with regards to him assuming that because I work for myself that I can have time off whenever I he want(s).
He was supposed to come over last night, but I cancelled due to running late on a work deadline. Said we could do something today in the day. It was left that he would call me in the morning and jokes were made about me likely being dead asleep if it was early and not hearing it etc.
At 6.30 this morning I woke to my phone buzzing. I saw it was him and ignored it, as had only got to bed a couple of hours before.
Then my doorbell buzzed.
I was annoyed that he just rocked up at my house (15 miles from his) at 6.30am with no prior warning. My phone kept ringing so I decided to ignore it. He continued to ring the doorbell, long sustained buzzing 10-12 seconds.
I keep my window which faces the road open most of the time (first floor flat). He shouted through the window "ALEXA! TURN BEDROOM LIGHT ON!" which of course she did. Okay, annoying but maybe, just maybe he was kidding around and didn't think it would work.
Then he shouts, "ALEXA! SET ALARM FOR FIVE MINUTES"
I lost it then. I went to the window, said, 'Well you can fuck off', slammed it shut and locked it.
He then continued to ring me and buzz my doorbell until I threatened to call the police. He then resorted to just yelling up at me from the street"
I was horrified that he was shouting up from the street at 6:30am on a Saturday, I ended up going round to all my neighbours and apologising
I never saw him again.