画蛇添足 (Huà Shé Tiān Zú), “drawing a snake and adding feet”, is a useful idiom that warns against adding unnecessary frills to something that’s already complete.
You know what it’s like. There’s only one cup of booze left. Everyone wants it. What do you do? You hold a snake-drawing competition (of course?), and the first to finish gets the prize!
However, when this happened in ancient China (we’re told it did), the first person to finish his snake looked at it and thought “ha, the others are still at it, while I have time to spare! I’ll draw four feet on my snake just to show off!”.
However, when the referee (there must have been one) reviewed the snakes, he awarded the prize to someone else. The reason? Well, snakes don’t have legs, silly!
The moral is clear: Don’t overdo it.
See? It looks really stupid. Author’s work