"x is an x, except it's not. While seemingly simple, there are many
considerations that go into the proper make and use of x. They are the
_______ (metaphor) of the xy industry."
- "(proverbial) booger on the finger"
You asked for a metaphor, not an established metaphor. This metaphor would be a great hook because of its crassness, but its crassness ends up being excused by its aptness. That's because getting a booger off your finger always seems easy.
We've all been there, rubbed our hand across our nose and found a booger stuck to the side or back of our finger. It's an easy enough problem. Just flick and it's gone in less than a second, right? Wrong.
Time and again, it proves to be much more difficult than that. You spend the next 10 to 30 seconds flicking and having it to this finger and that finger, but you're never rid of it. Soon you're walking around for another 30 seconds looking for something you don't care about that you can smear it on. Aha! The underside of your desk. You start smearing, but it doesn't stick to it. You try for 10 or 15 seconds, and still that booger's on your finger. Now you end up having to get up and go get a Kleenex or some toilet papers or go wash your hands. What seemed like it would be one easy step that you got done in a fraction of a second, ends up involving you in a multitude of steps that take 60 or 100 times longer than you had originally thought.