I have IBS so it's like a lottery on that type of thing. Sometimes I am ok, and the others I get hit with a nasty case of painful "OMG MUST GET TO BATHROOM NOW" and am stuck in there for a couple hours.
The worst was on the way home from a trip to Rockford, Il. We were on the freeway and there was no where to stop for a bathroom break, but I got hit pretty hard with the abdominal pain and diarrhea. so had to go find some bushes. NO TOILET PAPER! Nonetheless it was VERY VERY BAD. I hope I never have to revisit that situation. I keep toilet paper in the car all the time now.