After I typed the title to this post, I went huhhhhhh? I'm always saying that -- but, never thought about what or where that came from. So, I did a little googling --
Leave well enough alone - to allow something to stay as it is because doing more would not improve it.
The idea behind this expression dates from ancient Greek times, specifically Aesop's fable about a fox who refused a hedgehog's offer to take out its ticks lest, by removing those that are full, other hungry ones will replace them. Put as let well alone from the early 1700s, it was first recorded as let well enough alone in 1827.
After lunch, I decided that I would take my high-key portrait and do a little more dabbling in Photoshop. Popped the picture open, added about 9 layers of texture -- and here we are -- the revised self-portrait!
Anyhoo -- here's "Can't leave well enough alone"