But still, if you're retiring with $3 million, you're clearly well ahead of your peers. A $3 million nest egg gives you the leeway to spend money on the things you've always wanted to do - especially if you're also getting a generous monthly Social Security check. Still, a $3 million nest egg needs to be managed carefully. You don't want to blow that money or risk running out of savings in your lifetime.
A nest egg of $18 million per year is very large. At a safe 3.7% withdrawal rate, the Redditor could spend $666,000 per year. Since the OP said he's spending $300K plus his mortgage payments, he's most likely well below that amount (depending on just how much the mortgage balance is). Since his income needs would be more than met by his savings, there's really very little reason to continue doing work he doesn't enjoy.