Almost everyone could've got the same feeling. None expected bitcoin market will turn this big and there will be such a level of growth in the short term. As said in the OP,  what volume of transaction have taken place in our wallets. We could've kept something for the future, because the price at which I saw bitcoin is around $300 and what is the price now. Opportunity have been missed, but the market have given access to buy/invest based on ones affordability.

It is volatile, but it was not created to make you wealthy anyway, it was created as a p2p electronic cash, one that's permissionless and decentralized. There is nothing bad to take advantage of its volatility and make money if possible, but i just wanted to point this out, so people don't find it strange when spending their BTC's.
Why would you be depressed spending your "money", except you squandered all of that on unnecessary stuffs, i don't see why you should feel sad, you can't save all your BTC's, spend some when you get the chance to.

I can no longer talk about the errors I have made in the past for not saving or accumulating bitcoin. When I had the chance to do that, I barely even visited my transaction history for my old wallets. This is because they are heartbreaking, they bring regret and discouragement, and you can also be encouraged by them if you choose to face reality.
 
To me, the issue is not with me not being able to save in the past, but now, based on how I treat the information I have on my table, now that I have realised the mistake I made in the past, how much I have saved and accumulated so far is what I should be worried about right now. In order for me not to use today's experience as a regret again in the coming future, I can use it for testimony instead.
 
Bitcoin is an asset; it is also wealth, so whenever we choose to start accumulating, even after wasting it in the past, it will still be beneficial in the coming future.

Yep, this is normal and the majority of us for sure experienced it not only you but of me, yes. I also tried to calculate the value of my Bitcoin if they still have it now.
We have many mistakes from the past but it became a lesson, especially when I converted my Bitcoin before to random altcoins.

Agree with you it's never too late for it, I am also stacking every satoshi that I can.

I did not move much bitcoin before, my first wallet doesn't have many transactions but it is from 2011, almost 12 years ago, yes we missed the opportunity but there is no way to feel regret of that, it is sad but we can't change anything of that feeling on that way, then IMO is better to look at the future with better expectatives and begin informed about bitcoin and its technical topics will be good for all of us

So, keep stacking those sats and stay curious. The bitcoin game is still young, and who knows what's coming next

We have still 29 halvings to walk for a while

I think everyone would have experienced this and would have regretted that they spent the bitcoin when it was so cheap. On the other hand, if they could hold on to the bitcoin, they would be millionaire by now. I have spent bitcoin under 5000$ too and at that time I was so happy but later when Bitcoin reached 19,800 at the peak of 2017 bull run, I was so depressed.

Anyways, we always learn things with experience. Now I do not spend Bitcoin unless it is extremely urgent. I keep holding and wait for the next bull season to cash out some of my bitcoin. You can accumulate too as much as you can. I know that owning one full Bitcoin is not so easy nowadays but still, any amount will be good. You would not want bitcoin reach 100,000$ and you do not have any portion of it.

Although we nay regret for not saving any bitcoins earned from the past still I'm glad that I still use this up till today and just move on with that chapter since at the end of the day we happily use that balances on any means. And for sure we are so satisfied at that time so maybe learn to move on from those but instead make that amount pass on your wallet as inspiration to gain more. Since for sure if crypto will exist for more years we still have many opportunity to gain a lot of money from our investments.

When I first purchased Bitcoin, the price was only a few hundred dollars. A few coins was a relatively small amount. I accumulated double digits in Bitcoin. And I also had a number of altcoins. Valued in Bitcoin, at the peak of my crypto portfolio, my worth must already be considered huge today.

It's understandable to feel a little bit sad looking back, but we don't have any control of the past. I've probably learned my lessons, and although the same opportunity won't be coming back anymore, I'm kind of making up and am more determined to hodl.

Thats probably the most of us are feeling. I haven't look at it since 2017.  I just look at it now and it felt like this could have a lot of coins if I just did the right thing during my first experience of bullrun. I was unaware that bear market could actually drain the price down. If I was just aware, I would have coverted all to stablecoin.