The thing about people decorating their houses in colors that are flattering to them is true. My mom sells floor coverings (carpet, tile, etc.) and she says that when a someone comes into the store, she takes them to the carpet or tile in colors they would look good in - and she is really good at judging things like that. She says it's particularly important when someone comes in asking for a color like gray, yellow, or beige, which can be warm or cool and come in so many shades.

Of course, people are also influenced by trends. Which explains the 1970s, and well, all periods since then.