What makes a doubt that stays with you?

I was sitting in the church this morning, just before service, and I kept thinking about how some doubts don’t go away—they settle in like old furniture. Not the kind that shakes faith, but the quiet ones: the ones that ask if you’re even listening anymore. What’s the difference between a doubt that passes and one that becomes part of your prayer? I’ve been wondering if the real test isn’t belief, but whether you can keep company with the question.