Douglas Adams

An S.E.P.,' he said, 'is something that we can't see, or don't see, or our brain doesn't let us see, because we think that it's somebody else's problem. That's what S.E.P. means. Somebody Else's problem. The brain just edits it out; it's like a blind spot. If you look at it directly you won't see it unless you know precisely what it is. Your only hope is to catch it by surprise out of the corner of your eye.