Most professionals will reach a point of sufficient experience where heuristic* thinking takes over. Radiology is no different. So, yes, I suppose we all become comfortable in the sense that you're asking. That is, I don't go to work each day struggling to find the words to describe something, outline an appropriate differential, or park a needle where I want it. I still feel myself get a little on edge leading up to a call, but it's a healthy nervousness, I think, in that it let's me know I still care and gives me a heightened awareness (at least early on in my shift).
That isn't to say radiology isn't challenging. Apart from the breadth of knowledge required, radiology is challenging because the next I-don't-know-WTH-that-is case is always right around the corner. And we never know when that study is going to pop up amid the stack of otherwise routine, garden variety exams. The job requires one to be able to quickly and adroitly switch from heuristic to analytical thinking, lest the single lung cancer case go unnoticed in the middle of the 50 other normal chest radiographs.
*I'm using heuristic here to mean an intuitive judgment.