One of my biggest surprises is that I am spending a lot more time thinking about optimizing (income) taxes than I did when I was working. When I was working, I was salaried and most of my income was W-2 income so there wasn't much I could do other than max out the 401k/HSA, etc, fill out the forms and pay the amount due.
Now, with virtually no income other than dividends and capital gain distributions on taxable accounts, the possibility of 0% capital gains, Roth conversions, optimizing property tax relief, etc all come into play so I'm spending more time tax planning then I ever did.
One thing might be that I have the time to "play" around with it more than when i worked, so I do.
I play a hell of a lot more golf too.