Obviously, topics like religion etc. are taboo. It's on IT topics that you'll have problems. Everybody is an expert on computers. The client won't understand why things don't work the way he/she thinks they work. You are just obstinate if you say something should be done in any other way, but the way the client wants. Oh, the joys of a career in IT. In one Tech Republic article I remember reading that satisfaction with IT departments was 18%. Yes, terrible people us. We can't make every whim of the client a reality. But don't tell them that their ideas are stupid. Don't even start laughing when they say something especially stupid, which will be often.