It has now been eleven hours and fifteen minutes since I had my third shot of Moderna as a booster. No side effects whatsoever.
The only problem I had: I took a Lyft car to my doctor's office just in case I did get woozy or otherwise didn't feel like driving home. When I came out of the office, I felt fine but when I went to call a Lyft to take me home, I discovered that my cell phone was at 2%.
I don't think that was because of the shot. I think I have a defective battery and I've made an appointment to take it in tomorrow and have a new one installed. But this afternoon out in front of the doctor's office, I quickly shifted to Low Power Mode and summoned a Lyft. The car arrived just as the phone went deader than a right-wing anti-vaxx radio talk show host.