Imaginary obstacles are insurmountable. Real ones aren't.

Real obstacles don't take you in circles. They can be overcome. Invented ones are like a maze.

There are no insurmountable obstacles

Theatre is a series of insurmountable obstacles on the road to imminent disaster.

She preferred imaginary heroes to real ones, because when tired of them, the former could be shut up in the tin kitchen till called for, and the latter were less manageable.

I've seen many troubles in my time, only half of which ever came true.