>Not all useless things are bad of course. For example, useless knowledge is sometimes the best kind.
>
>Did you know that the safety pin was invented by Walter Hunt, and he sold the patent for next to nothing? See, even though that is pretty much useless knowledge, it is still good stuff. Same as knowing what Tom Waits means by 'on the nickle'. What good does that do you, but you still feel good knowing. Or, maybe it's just me. ;)

We have a pretty useless proverb: "who knows what is that good for", in more known version "who knows why that is good" ("ko zna za šta je to dobro" vs "ko zna zašto je to dobro").