What an odd and sad little moment.
I think we're supposed to go away from this feeling optimistic and uplifted, but if you pay attention to the lyrics, the message is much more ambiguous.
Yes, there's always a tomorrow when dreams can come true, so hold onto them. But the reality is that, when tomorrow comes, we have much to do and get caught up in the affairs of the day. So, another day goes by with our dreams still unrealized. This is simply life, and how it will always be.
So what is Clarisse trying to tell Rudolph? To stop fighting it, and to just let what will happen, happen? To realize, if only tacitly and subconsciously, that wishing is most often futile?
It really doesn't match up with the cute woodland creatures, but for precisely that reason, I find it poignant and quite beautiful. Even in the world of adorable puppet people and eternal holiday cheer, life is hard and disappointments are inevitable.