Missed Coin Opportunities You Regret

I keep kicking myself for not buying more silver when it was in the $14's.

Also for missing the 2017 U.S. Mint Congratulations set.

I *almost* sold all of my silver on ebay when it hit $47/oz. I got cold feet and didn't do it. I only had like 5 ounces at the time, but still! My dad had ~30 pounds that he had bought at $8/oz, but he said "When it seems like a good idea to let it go is when you really need it the most." Never did ask him if he regretted not taking my advice.

I also regret:
1) Not buying a 2012 proof set, because that was the year I got married, and I want one.
2) Not flipping all three of my 2015 March of Dimes sets.
3) How much I wasted on "Oh that's a cool coin!" Rather than picking a goal and sticking to it.
4) Couldn't even count the number of times I saw a rare coin I needed go for peanuts on ebay... after bidding was over!

My regrets always involve thinking longer than I should. Especially on buy it now items. A few times I didn't check my want list emails until the afternoon and those great buys were already snatched.

The good news is I never regret what I do buy now that I'm psychotic picky.

Two misses come to mind.
1. A 1941 Sarawak 1¢ piece back about 15 years ago. Probably less than $1000 at the time.
2. Within the last year or two a British 1941 Maundy set. Right around $200.

(1941 is my birth year.)

Thanks for the post Force, because of it I bought a set last night thinking "no regrets,no regrets". Good deal (12.99) on 2004 (Canada Goose loonie) Specimen set. I have one now, so this one will get cracked and into 2x2's they go. Finally filling the 04 50 cent hole.

If I can turn back time?

Oh! That tune keeps ringing on top of my head!

In late 2010, when I was barely starting to collect semi-seriously, I was sent out to the Izmaylovo Vernisage with $100 in spending money (as part of a meet-up with a visiting member of an alternate history forum... long story).
I came back with a few random purchases (overpriced, in retrospect) and $90 in unspent money. No, seriously. I really should've bought a gold coin if nothing else - back then the prices were low enough to allow that (still don't have any gold in my collection; I came close to considering it a few times, but the cheapest gold I've seen in the last two years that wasn't a tiny NCLT piece cost $140, and that much money is still beyond my limit).
I also was unable to find the promised flea market area in the back (which ultimately became my favorite part of the Vernisage once I did find it). Had I found it, I would have probably expanded my collection very much just that one day.

Then in March 2011, I received a $350 prize for an essay contest, and decided to spend it all on coins. I found what felt like a nice antique store, spent a few weeks discussing my possible purchases in comments on a numismatic blog (!!), and, receiving ever higher values for the silver coins I intended to buy, took the plunge around April 27.
If I just waited another week, I would have received a more reasonable value, and probably would never have spent so much money at that darn antique store...

One specific missed coin that makes me sad: a worn Chad 100 francs was offered for $4 way back when I thought that was an awful lot of money to spend on one (modern base-metal) coin (2013 or so, I think). The seller said it should've been selling for much more, I kept insisting that $4 was an awful lot of money.
In retrospect, the seller was right, and when I did get a Chad 100 francs (even more worn than that one) it cost me $7.

One missed opportunity of another kind: one time about a year ago, when I was working on expanding my country count, I saw someone's huge coin album on the Vernisage and asked if they had anything cheap from exotic countries.
"Oh, right, sure", the dealer said, "I'm sure you don't have that one. Afars and Issas, large aluminium, one dollar, should be right... about... here... I swear it was still there in the morning..."
Apparently some other guy bought that (fairly scarce) coin earlier that same day. I still don't have anything from Afars and Issas (not even the supposedly more common larger denominations).

...There are probably other major missed opportunities that I don't recall specifically.