The problem is the guidelines "work" in the sense you correctly figure out they don't have anything more serious and avoid any iatrogenic complications from aggressively trying to diagnose something that isn't there. The patients understandably continue to feel anxious and are constantly in pain because there aren't really great IBS treatments. So it basically seems from their perspective like the guidelines don't work, which is frustrating for everyone when they come back every month asking for further work-up when no further tests would really be appropriate to offer them.