Should of guessed.
I really should of guessed the tone of this movie when i saw Donald Trump in it. Just moronic humour for brainless tools.
Capitalism: *beep* on the little guy whilst making him feel like he has a chance.
It's 'should have'. You are hearing the contraction 'should've', which is a shortened form of 'should have', and you are mistakenly interpreting 'should've' as being 'should of' when in reality, there is no such combination. 'Should of' has no meaning whatsoever.
Similar misunderstandings occur, usually amongst people who don't read as much as they should, with 'could've', 'might've', and so on.
You probably want to go edit your post, where you have written 'should of' twice; it really makes you sound dumb, and broadcasts that you aren't a reader.