system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 why does cling film sometimes stick perfectly to some plates/bowls but other times it does not?
gpt
If you Google this, you get all kinds of answers.  The obvious one is how clean the dish is.  The cleaner the better.

But the real answer is how smooth the dish is.  If the dish has a very smooth and polished look, cling wrap clings better.  A matt finish is bumpy at the microscopic level, making less contact with the cling wrap.

And you might say "sure, but why would that matter?"  The answer to that is that much of the cling in cling wrap is an electrostatic cling, and only works well with very close touch.   A bumpy texture holds the plastic above most of the surface, only touching the tops of the bumps.

There is a small but real chance you are using cling wrap on a metal dish, and one that is very smooth.  What gives?  This often does not work because the metal discharges the electrostatic charge.  No static, no cling.  Glass works well because electricity does not travel easily through it, preventing electrostatic discharge.