Once I came home from work and my wife had gotten her hair done while I was away. When I walked in the door she said “don’t you notice something” to which I said: “the house looks clean?” “You’re making supper?” Etc. But I didn’t notice her hair. The reason she got her hair cut and dyed was because her folks were coming to visit us from Finland. So a couple days later we are walking around a pond with her parents and her dad (a big bird watcher type guy) is asking about the ducks in the pond. Why are they different colours? I say, “the male has the fancy green head to attract the female. The female is the plain brown coloured one because males don’t care about that kind of thing” then I turned to my wife in a very scientific way and said “which is why I didn’t notice your hair. It’s biology’s fault, not mine!” she didn’t think my observation had any merit.