Going without sleep does it for me. Had gone just over three nights/four days without sleeping. Ended up falling asleep at the wheel and driving through a phone poll. Nobody other than myself were injured luckily. I had just left a pt's house and needless to say people didn't like that . Was accused of being on drugs. Clean tests in ER proved otherwise. I kept my job, but two years later had another bout of going without sleep and passed out in a facilities lobby while doing paperwork. That was the end of that job. No good.