I have a tendency to overthink things.  It's how you make sure a job is finished.  If you don't overthink, you will miss something.  You might miss something anyway.  Being cavalier about the possibility of a mistake doesn't lessen the potential impact of that mistake.  It makes you an idiot.  It is necessary to far exceed your own personal expectations, if you want to meet the minimum acceptable standards for the job.  Intellectually speaking, you need a 20-foot ladder to paint a 10-foot wall.

As William Blake famously said in Proverbs of Hell, "You never know what is enough unless you know what is more than enough."  Of course, this line is immediately followed by the ridiculous claim that a "fool's reproach" is a "kingly title."  He was probably dealing with a lot of stuffy, unimaginative legalists whose only virtue was pragmatism, but it's a silly sentiment anyway.  The kind of thing a bunch of underthinking control freaks would drive a man to say.

Which is all I want to say.  I was recently informed that I was "overthinking" something.  It wasn't unfriendly, or even out-of-place in the context of the conversation.  But the phrase stuck with me.  And it occurs to me now:

If someone tells me I'm overthinking, I generally disregard that person's input on other matters in my life.  They're not thinking about anything, and so my thinking appears to them to be "too much."  This can lead to frustration and boredom if it isn't disregarded outright.  Don't ever let anyone tell you you're "thinking too much."  It might be stated in a benign, even harmless way, by someone who loves you and really wouldn't ever hurt you, but what they're signalling is INTELLECTUAL INCAPACITY or RESIGNATION.  For whatever reason.

It's not a sin, any more than brains are a virtue.

In any case, it is necessary to look far beyond the maximum capacity for failure to minimize the occurrence of unforeseen destructive variables.  

Enough!  Or too much!