He wanted to know a good TV and speakers for around $3,000 to use in his newly finished basement for a quasi-home theater room. I recommended getting a plasma TV and to look at the Panasonics if he could find any or maybe a projector. I cautioned him about how TVs look in the stores. I suggested he stay away form the proprietary HTiB options and explained why. (I did mention that Denon and Onkyo has options and why those would be better than the Sony\Samsung ones). I told him that a good speaker system would be more than the cheap ones but would easily fall within his budget.
He came in today and told me about the Philips TV he bought (because it looked good in the store) and the sony HTiB he bought because the salesman recommended it.
I have no doubt it was cheaper - he probably spent around $1k - but for someone who went on and on about how he wanted a great picture and sound...well - it was definitely a waste of time...
That is where qualifying questions beforehand often will save you some trouble. Any normal that really cares about quality will WANT TO spend $3k+ and will say it up front. If they just throw out "I want great picture and sound" without a solid budget (aka "under ____" is not a solid budget), what they mean is "I want the best of the cheap stuff." Then you tell them some general advice (only get a 120hz model) and move on.
Personally I never get offended if they go another direction as long as I am not required to support it. Life is too short, so if someone wants crap let them buy crap.
Where it upsets me is if it is a family member and they will expect me to support the device after they discarded my advice. That is uncool and what gets me upset.
But that is why in those situations, I am MUCH more firm. Something like "buy this exact model off Amazon or I swear to God your universal remote won't work well anymore and I won't help you fix it!" I make it clear they will lose every dollar they save going cheap paying the geeks at Best Buy to do everything for them. I have gotten to pick every TV in my family for years this way.