If it ain't broke, add more features.
I heard this quote last week at the HFES Conference. It is so typical, but I like the contrast with the other cliches. So many systems add more and more features for every new version/model/or whatever come out. Its like the Peter Principle. If the system is usable, more features are added. When it is finally not usable anymore, they stop.
I heard another quote which was from a doctor during laparascopic surgery. He said "move it down, up the axis." What the heck does this mean? The other doctor didn't know either. The presentation was a study of communication during surgery. There were lots of other examples like this. Even simple statements like "move it to the left" are ambiguous because you can't tell if he meant his left, your left, or the patient's left. It makes me very afraid to get sick.