At about hour 9 at one bathroom breaks and zero water or snack breaks, I'm mixing my patient's smashed BP meds in water so I can give them down the NG tube when I look at the monitor to see that his blood pressure has tanked for some unknown reason. As soon as I process the information in my brain, the next thought that pops into my head is "I wonder if I drank this if I would have a syncopal episode and be able to go home?" Mind you, this is never something I would do or even consider doing, but for some reason like, some other part of my brain took over and was all, "screw this! self destruct!!!" Luckily (?) the generally sane rest of my brain was like, "that isn't cool, plus you're not wearing your cute panties, so you can't pass out here," and I finished my shift relatively uneventfully other than the general awfulness.
So, I guess the moral of this story is, when your brain tries to kill you, it's time to stop picking up extra shifts.