This is a good question to use on any pent up anxiety or concern. It is an excellent first pass to get to the real rub of the issue.
It’s even more potent when you don’t have any concerns about what you’re about to do. Optimism is more blinding than pessimism.
The younger one is the more clarifying this question might be. The reverse, what is the best that can happen, is too hard to know and probably too irrelevant. Process is more important than outcome.