I work as a reading teacher, and these dayts, I tutor for a few hours a week. Ostensibly, I ought to be able to diagnose a child's reading difficulties, come up with a plan for remediation, and carry it out. I've been trained to do these things, and I enjoy my work.
But, like all people, I worry about my effectiveness. I'm sometimes plagued with the thought of, "I hope I can actually make headway with this child." Not because I perceive the student as ineducable (haven't met one of those yet). Not because I don't have confidence in what I need to do (although sometimes I doubt myself, as do we all). But mostly because sometimes, I know that you can do everything you are supposed to do 'by the book' and it still may or may not happen.
Sometimes there are underlying issues that you aren't aware of, be they emotional, neurological, or otherwise, that will stand in the way of the effectiveness of the work. Sometimes the rapport between a student and a teacher doesn't create the most conducive learning environment. Sometimes a student's retention is weak, and the headway you make during one session is lost the next.
I currently work with two great kids. One's father is a marine. The other's father wears a long beard and peyos. The boys are almost the same age. Their issues differ, and their lives differ even more. But in each case, before and after leaving their homes, early on a Sunday morning, late on a Sunday night, after Shabbos, or on weekday evenings when my own mother tells my kids that Mommy will be home shortly to get bathtime and bedtime underway, my silent thought is the same, "I hope I can help this child."