[Barrett]

Wayne and Michael both make strong cases. The only thing I'd add is the testosterone factor: young (some VERY young) men already selected for their Type A personalities were placed in not only a highly stressful but highly competitive environment. Couple that factor with the feeling of peer pressure and Victorian obligations to perform well and "do one's duty", and you can well understand how many of those folks pushed themselves to the limit--and beyond. That goes a long way toward explaining men like Guynemer, Nungesser, Berthold, et al. Remember, these people were OLD at age 25; 30 was ancient.