I think my facade slipped today
What does it mean to have your facade slip?
It means that you have worked on presenting a certain attitude, but it turns out that the people around you can see you in a way you weren't ready for.
You are better off just staying true to yourself. Living as someone else is only going to make everything around you more incompatible.
What if we are true to our facade and people don't accept us as we are?
If someone does not accept you for who you are, it's better than having someone accept you for who you are not. You should always strive to be your best self so that you are not misunderstood.