I can definitely see your point. And to some other comments, this actually applies to a great deal of people in the working world. Also anyone with spouses and or kids or the simple unknown occurrences that happen in all our lives and can't be ignored it's simply not always possible to jump on for a special mission that is only available that day. That said, I think the spontaneity is fun. But a work around could easily be added for those who didn't have the chance to run it. Maybe a quest line that has some sort of timed gating so that it couldn't be run right away but after a short period could be accessed (without a dependence on sheer random availability). Just a thought, but Bungie definitely does need to put some thought into this so as not to screw people out of the opportunity to earn these great rewards.