Paying customers can be great.
They also can be mouth-breathing assholes who expect the guide to make fish bite and get pissed when they don't. Fish don't always bite, even for the best guides and pro anglers. Yet the paying customer believes the guide is a magician who can automatically make it happen.
The guide has to be nice, friendly and chipper no matter what. Even if he's done everything right, mouth-breather will wander off to tell his buddies that Bigtime Pro Guide couldn't catch a fish and he wouldn't fish with him again ... yet he doesn't talk about how they stopped at X-number of places, tried 29 different lures and tactics and did everything possible. All he says is "the guide sucked."
If you can put up with those days, and those should be far fewer than the good ones if you're a good guide, more power to you.
Don't forget that half of the mouth breathers own a boat and think that because they paid you to take them fishing one time they are entitled to every fishing spot you took them to from now on.