The seamy/seamier side (of something) phrase
The unpleasant, disreputable, or base parts or aspects of something that we normally do not see.
It’s all too easy for kids to stray into the seamy side of the Internet.
Parents are encouraged to use filtering software to keep their kids away from the seamy side of cyberspace.
It’s well known that school has its seamy side: bullying and favoritism.
This expression alludes to the wrong side of a garment or other fabric, in which the stitched seams show. It was first transferred by Shakespeare, “He turn’d your wit the seamy side without” (Othello, 4.2), and has been used ever since to describe the unfavorable side of things.
Used to express something bad is happening again
Here we go again! Lisa has just asked to borrow my new dress.