Giving a quote for repairs or his/her opinion on why buyer should (or should not) buy a home Michael Thornton - and that's the end of the relationship!

If he give his opinion as to whether the buyer should buy the home or not, he is off the list for good.

Lie about what he finds.

Talking to my clients about things they have no knowledge of.

If my inspector told the buyer what to ask for and what could "kill the deal".

When an inspector is extremely anal or not detalied enough, I will move on. I once had an inspector get over-involved, arguing with contractors that they were doing repairs incorrectly...it was too much...stopped using him.

Make a buying or not-buying recommendation.

Debbie nailed this one!

We don't hire them the buyer does.

Michael -- just one?  Unprofessional conduct.  

The #1 thing that home inspector do that I do not like is scare my buyer about the issues with the home.  #2 Is not calling me of my buyer back.

Not returning a buyers phone call in a timely manner.

Missing an obvious issue.  Had it happen to me on the home I bought last year

I once had an inspector talk down to my buyer clients as though they were in the third grade.  He interrupted the wife on several occasions, and by the time the inspection was finished, I vowed he would be dead to me.  He still is... 

Good morning Michael. Love the question, some just do very sloppy work and delve into areas and give opinions on stuff that they shouldn't.

Kill a deal with unreasonable items.  Many Buyers; particularly first time, believe everything an inspector cites and thinks they are bigger issues than they really are....an inspector needs to be professional and helpful to the client and explain issues honestly.  Don't lead them to believe they should received $$$ for everything awry.  Explain to them how they should maintain the appliances.  If the inspector is slothful, disrespectul and messy, they will not be used again.