Being a home theater installer I run into all different kinds of customers. On a few occasions I get the privilege of running into a customer that believes he knows everything. What we end up finding out is that they know absolutely nothing. They tell me that they read the box, and it stated that it did what they wanted so it should work perfectly.
I have installed almost every manufacturers equipment at this point in the game for me. The more difficult ones to install are usually the Denon systems. I usually recommend things that I find are cost effective, and also good performers.
After I am done with installations, and I have things working as best as I can I have had a customer, or two tell me that it isn’t right. Well, at that point I usually just call into our tech line and have a supervisor explain that what we have done is it. Those customers are usually the ones that complain the most, and still know the least.