A rule of thumb:
1) If you are conservative (or retiring young, or likely to live long), then each year you can spend 4% of what you have saved. Thus, $2M will let you spend $80,000 a year. Yes, that is comfortable for many people in many locations. But, it isn't an excessive or lavish lifestyle either (remember that one cancer medication could easily be half of that amount). The goal in this case is to maintain the $2M, so that you always have money. You will probably will give your heirs quite a big lump sum when you die, but in case something bad happens, you have that $2M cushion at all times.
2) If you are aggressive (or retiring much older than the typical retirement age, or likely to die sooner), then each year you can spend 6% of what you have saved. At $120,000 that is a pretty comfortable life for most people. The goal in this case is to have money for your whole life, but to die penniless.