The phrase "mad shit" is used in slang vocabulary to describe something that is favorable or out of the ordinary. It is usually used among males in their teens to denote something which they see as awesome or cool

From STEM, an abbreviation short for "Science, Technology, Engineering and Mathematics", a STEMlord is a pejorative term for a particular kind of person who has studied in these areas at university or works in these fields who holds a pretentious, condescending attitude to anyone who has studied in any other fields, particularly the Arts and Humanities. They typically believe themselves to be more "intelligent" and "rational", while generally remaining incredibly ignorant outside of their areas of expertise and having the charisma of a rotting pig's backside.

The kind of shit that makes you feel as if you did something that made your shit angry, with no regard to your butt holes well being.

this term means "bad mouthing" write bad reviews about somebody.

When you are taking a shit, you make angry or mad faces while pushing the feces out