Regret

It's natural that those with more opportunities tend to have more regrets. However, as a way to cope with negative emotions about choices, gaining the wisdom that you'll regret any choice you make is valuable. Not having any regrets at all would indicate sociopathic tendencies or brain issues. But knowing how to deal with regret and grow from it is important. If the regret involves a judgment that would have required knowledge of the future, there's no need to dwell on it. Otherwise, determine whether it was not the optimal decision based on the information available at the time, or if you simply didn't try your best. Feeling wistful is sufficient for acknowledging that you couldn't fully enjoy something good.