Watch the Denzel Washington scene from Philadelphia https://www.youtube.com/watch?v=AR6eXWNJzoY
This is F & F, not a VC. Elevator pitches make F & F crazy - and should. This is your emotional support group, not an investor that screens thousands of plans to get to a few they listen to to invest in even fewer. This is the group that will nod and shrug when you miss another soccer game, family dinner, public event, but still, without qualification, love you. This is the group that, almost as important as financial investors, you need support from to rationalize why you are upending your life to follow a vision that could make a difference. And they not only do not get why you do it, they do not get what you do.
I would pick one thing about the world that you will change is successful. Build on that to tell them why (if they actually ask) why you want to do it. For example, I am building a plan to make water safer, cleaner, and better while saving energy and time. If someone then wants to understand that, then we can talk about it. The bad news is most F & F do not/cannot understand what you do. They are asking a different question: "Are you OK?".
What is great about these conversations is that simplifying the story for them simplifies it for you - and anyone you meet in the business world. We are all tired of buzz-word-bingo - and straight shooters are more valuable than smoke and mirrors.
That is just my opinion. I could be wrong.