My deepest golf regrets all surround NLE's.
I grew up in an area (Central Indiana) that went through a quite delightful spell of very high-quality golf course construction in the last quarter century. The courses are terrific and for that I and many others are thrilled.
But in several cases, building new tracks meant obliterating old ones.
Gone are the original courses at Indianapolis Motor Speedway, Fort Benjamin Harrison, and Woodland Country Club.
And I never played them.
I lived a chunked 3 iron from Woodland, so I could easily have hopped the fence and played it as a kid. And I threatened to do just that several times, but I never did. I guess I regret my lack of delinquency.
Speedway was very easily accessible, but trips to the track at tat time of my life only meant roaring motors and track records; as a teenager it honestly never occurred to me to play golf there.
The original course at the Fort would have been a tougher task for a teenager - it was an active military base and restricted in the usual fashion. But still...
There were two other NLE's that I did play frequently - Sunblest and Sycamore Springs. The former was -objectively- awful... but it was mine.
The latter was better than it had a right to be, though it stood no chance when developer dollars came calling. I have enough memories of both to miss them, so there are no regrets.
As for more conventional regrets? I had an opportunity to play Sanctuary a year or so after it opened, then I tore my ACL, MCL, and PCL trying to score on a passed ball in a 30+ league baseball game. I guess I regret the steal. It was karma - we were up 9 and I was trying to end it early. Instead, the golf and baseball Gods conspired to punish my lack of sportsmanship doubly hard.
I was also kindly offered a round of golf at Denver Country Club. The gentleman extended the offer on the tee of the 17th. Then I closed him out on the green of the 17th and he acted like we'd never met. I didn't push it, but I do hope to play there some day.