Who are the Real Liars?

My fiancee works in the car business and has for the last 15 years. He is one of the most honest people I know. It breaks my heart when I hear someone say in causal conversation that car salesmen are sleazy, thieves or liars. I can't tell you how many stories I hear from him on clients lying about their income or the condition of the car they are trying to trade. You hear the same about Lawyers and Politicians. These people are no different then any other professional. I would love to hear from those folks who are blacklisted because of their profession and examples of the liars they deal with.