There should be no regret for not being able to buy a meme coin because it is nothing more than a gamble, if you can't get in too early, you will only waste your money by buying billions of tokens that will be worthless once the hype is over and if you buy when there is FOMO, you are guaranteed to lose money because the price will dump right after that and it has happened a lot of time.
If someone regrets not investing in BTC or ETH when they were at their lowest and they knew about them, that is understandable because they have probably missed something that they won't get to see again, or they may, we never know what the future beholds.
Investing in market ventures solely for the sake of FOMO results in either a profit or a loss. Regrets are reserved for those who have missed out on both past and current market projects. There are innumerable projects out there that we have lost out on due to FUD, but we kept it to ourselves so as not to be influenced by the past market condition. Every day, new opportunities emerge in the market; it is our responsibility to set things right for ourselves; we cannot change the past, but we can fix it with new prospects in the future.