The biggest factor in getting something to go from hard to easy is normally exposure. The more you encounter something, the less intimidating it gets. Your emotional relationship changes. There’s less uncertainty, your skill in dealing with it improves, your resentment for it fades, your craving for ease or salvation disappears. It has become easy.~ David Cain from, https://www.raptitude.com/2013/03/how-to-make-hard-things-easy/
That is so obvious, yet it’s so worth repeating.
What lies outside your comfort zone? Growth.
Yes, there are other things beside growth, outside your comfort zone: Fear, danger, and mistakes, for example. Irrational fears you know you should work through. Danger you know you should avoid. But what about mistakes? When’s the last time you made a mistake?