Those are good thoughts about selling only when you must. Those that have plans in the longer run, there is a bigger plan if you are not going to sell now. Some have already sold even before crossing $100k mark and that's fine, it's their plan and goal that must have been hit.
But if they have no plans of accumulating again, they're missing the bigger part. IMHO, if something big has already been achieved on their lives with the help of Bitcoin, that's okay.
We only live once and we don't know if we will still be alive tomorrow and so, selling for those important matters and events of their lives, there should be no form of making them regretful.