I have made many glaring mistakes in my life (many of them trying to be hetero), but 2 stand out:
1. A correspondence a with a young apoliticial woman in Karl-Marx-Stadt in the GDR, doubtless read by the FBI and passed on.
2. Writing to General Sec'y Brezhnev urging him to cancel a meeting with #Nixon during the SE Asian war, whom I characterized as having blood on his hands. I doubt that was passed on, but I'm sure I was redflagged by the FBI