My heron buddy was extremely well behaved and well mannered. He would stand about 10 feet away and watch for for hours. What surprised me the most is that he remembered over the winter, even though I hadn't fished for 3 or 4 months.
I felt a bit bad because over the course of an evening I might catch 20 or 30 fish, and would release all except the one I would toss him. He didn't seem to mind since he always came back.