What I wrote: "I'm just curious as to whether this is a common phenomenon with age, or if it's just me."

I did not intend that to imply that I wanted to hear about people's specific regrets - my apologies for not being clearer.

And "the phenomenon" I'm talking about is not so much a "mood of ruefulness" as much as regrets in the form of memories (however one understands memory) rising unbidden to the conscious mind, moreso with age. And I'm not talking about "dwelling" on them, or dealing with them one way or another philosophically, just the fact of their manifestation.

I think I can already conclude that this is not a common phenomenon, given that almost no one here seems to get what I'm talking about. Thanks everyone for giving it a shot!