As being a Bioanalytical scientist, I deal with a lot of clinical and pre-clinical studies. My biggest disappointments are when other scientists overdose animals and research are been called off. One time, they inadvertently overdosed monkeys and after testing 580 samples, I came to know company called off the study due to monkeys dying right and left. Also, being GLP study, they had to have certain number of animals as a requirement, so even though only couple of them passed away, they still called it off. Human samples biggest failure is controlling them and their behavior. I feel animals are much easier to control than humans especially in food and water.