Scorpiomikey:As someone who spends all day creating engineering drawings, it becomes easy to disconnect yourself from the end user, you know how it goes together, the instructions make sense to you, but when you pick them up 6 months later its usually "what the hell was i thinking?" its easy to do, especially when you spend all your time working on the 3d models.
It’s more common than that. I had what is sometimes called “a diagonal career”, and in every one of my endeavors, my co-workers had some phrase that covered the situation, “what was I smoking?” being one of those printable. I suspect it’s simply part of the human condition.