I’m not big on anniversaries, but who can ignore a plump number like 100?

This is my 100th column, a milestone considering that on my eighth, a light-hearted invitation to 85-year-old newlywed Spanish Duchess Cayetana de Alba to visit South Florida on her honeymoon, the morning’s email delivered this from a gentleman who copied my boss: “Dear Madam: You make me sick. I will never read another word by you. You should be thrown off the paper.”

An “ouch” moment, but I didn’t take it personally.

After all, I had prepared for column-writing by studying columnists around the nation, past and present, and all of them were moved to write about their “hate mail.”

My favorite was a story told by Anna Quindlen in her book Thinking Out Loud about New York Times columnist Tom Wicker, who at his retirement dinner read a letter he had received that morning.

“1992 is shaping up to be a good year,’’ the letter said. “First we got rid of Gorbachev and now we’re getting rid of you.”

It felt strangely comforting to read that before I began writing a column, perhaps because I knew what to expect. Like motherhood, writing for a daily newspaper is not for wimps.

I had the proverbial baptism by fire in the early 1980s by covering the Mariel boatlift and its aftermath, when I used to get regular mail from a Miami Beach reader who addressed every envelope: “Fabiola Santiago, Propaganda Minister for Miami Cubans, Herald Granma, Miami, Florida.”

We had good postal service then. His letters always found their way to my desk.

Despite the disheartening content about his hatred of Cubans, I missed the letters when they stopped coming. For years, I wondered if he had died or moved away, part of the so-called “White Flight” that turned Miami-Dade into a solidly Hispanic enclave.

Likewise, I’ve never heard again from my gentlemanly detractor who signed off with “regards” and his name. But I hope he’s given me a second chance and that he’s reading, regardless of his opinion on my job performance. Mine is only an opinion, a reported and researched one, but only one person’s view. One need not be so afraid or offended by it.

I do like hearing from readers, one of the most fascinating components of this job, the second-hardest in my career.

Often times a window into human nature, the myriad of commentary I receive — whether in letters delivered the old-fashioned way or by email or telegraphic-style by text and tweets — is like cartography.

They chart place and time, and are useful. The meaner ones often fuel my next column.

As for the indomitable Duchess of Alba, still my idol 92 columns later, she’s happily married to commoner Alfonso Diez, a long-time friend and state worker 25 years her junior who, to appease her children and evil tongues, renounced rights to her vast fortune.

Her health has reportedly declined a bit, but not her joie de vivre. She was photographed this summer enjoying the Spanish surf with Diez in a stylish pink flowered bikini.

Asked about the state of her year-long marriage, the duchess answered with two words: “ Muy bien.”