We regret about missing Bitcoin, then about XRP then about Ethereum then Doge then Shiba then Pepe (these are some top of my head and from what I've come across in my crypto term).
Point being there are always new opportunities and dwelling on regrets is futile.
There is nothing as an opportunity being missed as the prices retrace back and give us another opportunity to invest and take advantage of the surging prices. Some people do not understand this logic, and they just big high, thinking that train has been mised and they just do not want to be left out. It is at such times when they buy at higher prices and prices start to dump.
Patience is the key to trading and if you have patience you will not FOMO and most of the time, will not regret your decisions (as 80% of the time you will take the right entries)