Thanks for the thoughtful reply.
I think the hardest part is thinking about that future reward. If it is something that is days or months away it is so hard to rationalize sometimes. An argument can be made that we are not guaranteed tomorrow.
At the same time if waiting provides a marshmallow that can help you live a better life it might be worth waiting.
A common marshmallow involves no risk. If I eat it the only loss I have is the satisfaction I would get from the second. If we are talking about something that provides risk, that's when the choices become so much more complex and meaningful.