Byron Katie’s “Loving What Is”

I am revisiting Byron Katie after several years. I never understood the “loving what is ” concept- Below is from her :Little Book on her website and I am wondering if you could help me understand it. Thanks

“In a flash of insight, she saw that our attempt to find happiness was backward—instead of hopelessly trying to change the world to match our thoughts about how it “should” be, we can question these thoughts and, by meeting reality as it is, experience unimaginable freedom and joy”