Obviously the double connection helps that one stick with you. I recognize the import of that date when I see it, but otherwise I probably couldn’t tell you what date the Challenger blew up on: they weren’t the first astronauts to die in the U.S. space program, and they weren’t the last.
I think a lot of people are like me in that I know about events, but not specific dates. I believe that at dome level we all use some type of mnemonic (consciously or not), personal experience or interest to remember dates. If you asked me about the JFK assassination, I could tell you it was in 1963 and maybe November? And the only reason I remember it was 1963 was because I watched the news in 1968 about Robert and there so many references to JFK.
9/11 works because it recalls 911. What if it occurred on 9/10 or 9/12? December 7th sticks in the mind because it was “A day that will live in infamy”. Asks someone what 12/7 means and you would likely get a different response.
“In 14 hundred and 92, Columbus sailed the ocean blue.” What month and year? 
When was VE-Day? 1945! What month and year? May? , June? mumble Okay lingy, you got a 1 in 31 chance! 
My ex’s birthday was November 28, 1962 and to remember it I would mentally (sometimes verbally) recite November 26, 1968 (which was the final appearance of the rock group Cream), plus 2 days, minus 6 years…November 28, 1962! She would get mad because I put Cream’s date first, but I tell her “I knew them long before I knew you!”. Yeah, that’s why she’s your ex lingyi! :smack:
My first thought is “The day before our anniversary.”, and Pearl Harbor day is second now. I assume that’s a good thing
My grandmother died and Ronald Reagan was born on 2/6, my birthday. Neither comes to mind when you mention the date. Both are events I don’t want to remember. 
Also Gen X. I correctly guessed that the date in question was JFK’s assassination because I remembered he died in November, but I would probably not have been able to cough up the correct date if asked “What date was JFK killed on?” instead.
OTOH, I do know off the top of my head that Pearl Harbor was December 7th.
Thanks to Gillian Welch I know that April 14 was not only the date Lincoln was shot, it was the date the Titanic hit the iceberg (although technically it sank on the 15th, after midnight) in 1912 and the date of the Black Sunday duststormin 1935.
Gen Xer here, born around 1970. I know of 11/22/63 just from general chatter, but it’s not so emotionally significant for me since I didn’t live through it.
I know Reagan was shot in March 1981, though I couldn’t tell you the exact date.
Since 12/7 gets memorialized every year (and such memorialization always makes the evening news), the thought that anyone might not know of the significance of that date is a bit baffling.
November 22, 1963? C.S. Lewis and Aldous Huxley both died on that date.
This. I know JFK was assassinated in November, 1963, but it’s just one of many assassinations in the 60s. WW2 will continue to fade just like WWI did when the people who lived through it die off.