I was working only 12 hours per week when I retired, so I was already "nearly" retired. My short answer to the question, "How are you able to retire at 45?" was simply, "No kids, no debts." I had kept it pretty mum to my coworkers except for one trusted friend who was actually encouraging me to retire, often asking me, "Why are you still working here?"
To some other coworkers if they asked me, I would remind them of the exploding value of our company stock, something the company publicized all the time. If they had been working long enough, they also enjoyed that exploding value, even if it were in their retirement saving plan.
Because I had been working only those 12 hours per week (2 days), the transition to fully retiring was hardly a big one because I had already set up a good number of personal activities in the 7 years I had been working pat-time (going to the office 1-3 days a week, working 20 hours per week in the 5.5 years before reducing that to 12).
Another thing I kept mum, for the most part, was how the 2008-09 financial crisis greatly helped my ER and has done so for the last 12 years by presenting me with a huge buying opportunity I did not expect to have when I was planning it in 2007 nd into early 2008. That might have been seen as insensitive, at least at the time. Later on, I backed away from that statement.