Interesting thread, as I usually fish without a guide, but use a guide at least once a year or so even on my home waters. Why? Because they know the river better than I ever will and I have been fishing it for 50 years. But they are out 150 days a year, on all stretches, in all conditions, and really do know the water. I have had guides give less than great advice a couple times, but for the most part, they want you to catch fish and be happy. And all the good guides work at it. That is exactly why they are good guides.

Some of the wittiest, most interesting, "secure with themselves", guys I know are guides. They love what they do, and while they aren't getting rich, they are FISHING EVERY DAY!!! That is why they like what they do, and keep doing it. A good friend of mine has guided for years, works at a well-known lodge, and is one of their top boats. He and I have a deal. If we are just out fishing (or hunting) together after hours for fun, I get to ask him two questions pertaining to how we are fishing that night. After that, he doesn't have to answer unless I pay his guide fee.
Conversely, I don't cut his hair for free either. He makes money as a fishing guide. When I book with him to fish, I pay. When he comes to get a haircut, or his wife, they pay.