I think I can answer very close to this question from actual current experience. I reached "the number" about one year ago. Given
average investment earnings (assumed 4% real) and after tax savings from work, my NW is increasing at about $640,000/year (about 1/3 investment return and 2/3 saving), well short of your proposed $1M/year but still a very large number.
I was going to retire on May 1, 2014, but have made the decision to work one more year. Why?
1) I am still pretty young, a little under 50 yo.
2) My job is not stressful. Most would kill for my working conditions.
3) We started building our retirement house this year in anticipation of retirement and it is costing twice what I expected to spend. This will also result in double the property taxes I anticipated and somewhat higher operating cost (insurance, maintenance, etc). I feel the need to make up for this by raising "the number" a bit.
This was likely the most significant part of the OMY decision.
4) I feel stupid walking away from $640,000/year. Rationally, this is a dumb decision, as we have never spent more than $100,000/year (not including taxes), ever, and are currently spending about $70,000/year (not including taxes). However, I am finding it very difficult to make this decision. I think things like, "if I worked one more year I could buy my parents a nice house. How selfish not to do so."
The current plan is to retire May 1, 2015, about the time the retirement house is completed. I think this will actually happen unless the economic environment changes significantly, i.e. 20% or larger market correction or hyper-inflation.
In summary, I guess my experience is pointless with respect to your questions because I have not actually given up the money yet
.