Maybe I'm just getting an inaccurate perception, but based on reading threads here I get the impression that EPs who only work nights fall into the "that guy" category. That is to say most groups have one or two, but they're a quirky anomaly. Is that accurate? If so, why? One of the biggest complains about EM seems to be the constant screwing with circadian rhythm. So why not just stick with nights until a time when you have the seniority to do all days?