Marcus Aurelius:
If anyone can refute me—show me I’m making a mistake or looking at things from the wrong perspective—I’ll gladly change. It’s the truth I’m after, and the truth never harmed anyone. What harms us is to persist in self-deceit and ignorance.
Meditations 6:21.
It’s the jolt that you get when you’re snapping back from fantasy/ignorance to reality that really hurts.
The more you seek reality and stick to it, the smaller the deviation and the impact when reality’s gravity pulls you back. Make a jump from an elevation of 3 inches? It is nothing. Three feet? It’s a thing, but accomplished with ease with a bit of care. Thirty feet? Possibly fatal, certainly painful.
The ultimate snap back to reality, of course, is death. The greatest peril to you is in ignoring your inevitable death. Keep that single thought in mind (“I will die, and I don’t know when”) and you will be amazed at the clarity it brings.
And you would think it brings terror and inaction (“What’s the point?”). Quite the contrary. For me it has brought freedom from fear and impelled me forward to new ventures with glee and abandon. What’s the worst that can happen? I die? I’m already going to die!