“I can't believe you watch this stuff. It's so cheesy!”
Your sister is watching a TV show that you think is silly. You say this to tease her for watching it.
I can't believe you watch this stuff. It's so cheesy!
You say "I can't believe ___" when a fact is surprising or you want to show that you feel strongly about it. You can say this for positive things:
I can't believe we won!
or you can use it for negative things:
I can't believe you left without telling me.
When you say that something is "cheesy", it means that it's not good because it's too cliché or too over-dramatic. You use "cheesy" to describe movies, TV shows, music, books, etc.
Examples of things that can be called "cheesy" are:
- love songs
- soap operas
- cheap science fiction movies
- romance novels,
- bad jokes
...and so on.
"Stuff" can mean almost any physical items or material.
It's similar to the word "things", but "things" are countable and "stuff" is not. So "stuff" is better to use when you're talking about a group of things that are different from each other - different sizes, shapes, etc.
"Stuff" is especially used to refer to things that you buy or own:
But "stuff" can also mean "topics" or "ideas", like in this example:
We have a lot of stuff to talk about.