Thaxor:

I think the best way to explain trolling flies is that fly fishing is estimated by most to be about 90% presentation, and sometimes the sneakiest, most alluring motion an angler can impart on a retrieved fly can do nothing to compete with the hopelessly unnatural appearance achieved by trolling.

Like most, I prefer casting to fish, but trolling can sometimes teach me a lot about where fish are and how they are behaving in a given situation, and that makes it a valuable tool in my box. It also bears mention that there are days and places where it's the only thing that consistently catches fish. In my experience, Munn Lake is not one of those places, even if trolling is effective there. It is small, the fish are spread out all over the lake, and bugs are plentiful, all of which make it a great lake for casting.