Nasser had few personal vices other than chain smoking. He maintained 18-hour workdays and rarely took time off for vacations. The combination of smoking and working long hours contributed to his poor health. He was diagnosed with diabetes in the early 1960s and by the time of his death in 1970, he also had arteriosclerosis, heart disease, and high blood pressure. He suffered two major heart attacks (in 1966 and 1969), and was on bed rest for six weeks after the second episode. State media reported that Nasser's absence from the public view at that time was a result of influenza.

What was Nasser's principle vice?