What is the biggest mistake you’ve ever done, it could be when you were first starting out or, it could be now even experience to players make mistakes

My three biggest mistakes are related to champions. I sacrificed ninja, Scyl of the Drakes and high khatun and dark Elhain. I sacrifice these four champions when I was brand new and I had no idea how the game worked and now two years later I think about what I did every single day.