Being Richard Feynman didn’t keep the FBI from starting a file on him. It did, however, mean they stopped when he asked them to!
I don’t think I ever believed in Santa, the whole thing never really seemed plausible. Well, that may be my older self talking. Our parents never gave us the hard sell on it anyway, so to the extent I ever had any belief, over the years I eventually put two and two together and realized it was a story. No one ever had to tell me, and I didn’t have a traumatic experience of finding out he “wasn’t real.” But for those who have really bought into it, this seems a nice was to ease them out. (Or yeah, there’s always the don’t bamboozle them in the first place, but oh nevermind. BAH HUMBUG!)
And, best for last. Kermit the Frog covers the Talking Heads. Things like that can make you believe!