Until we learn to accept, we cling to things being the way they have been, or we wish they were, or want them to be, or hope they will be. We resist. When we learn to accept everything that comes into our lives, we are free from the pain and suffering of resistance.
And nobody said it was easy.
"Always go straight forward, and if you meet the devil, cut him in two and go between the pieces." - William Sturgis, clipper ship captain, 1830's.