The characters combine to paint a powerful picture: a “rotten stall” (烂摊子). It’s a situation that is not only messy and spread out (摊) but is also fundamentally broken, decayed, and unpleasant (烂). This is why it's a much stronger word than simply “a mess.”
The term 烂摊子 taps into deep-seated cultural values around responsibility and consequences. In Chinese culture, leaving a mess for others—whether for your family, your successor at work, or society at large—is seen as a significant failure of character. The act of creating a `làn tānzi` is the height of irresponsibility. Conversely, the person who steps in to 收拾烂摊子 (shōushi làn tānzi), or “clean up the mess,” is often seen as capable, virtuous, and strong, even if they are pitied for the difficult task they face. A useful Western comparison is the phrase “to pick up the pieces.” However, `làn tānzi` is more specific. “Picking up the pieces” can apply to your own life after a personal failure. A `làn tānzi`, by contrast, almost always implies a mess created by someone else. It also has a stronger connotation of incompetence and chaos than phrases like “a can of worms” or “a hornet's nest,” which focus more on the complexity of the problem rather than its origin.
`烂摊子` is an extremely common term used across all levels of society.