Bullshit, or horseshit, refer to misleading statements of fact. The active form of the meaning is often placed in the activity of feeding, eg. "That salesman was feeding you shit." Also, "Crock of shit." Or, as a verb, "That salesman was shitting you."
Chickenshit, however, is often an adjective, to describe someone who is unnecessarily fearful of performing an act his buddies are trying to talk him into (eg. "You're not going to call that cop a fucking pig, you chickenshit motherfucker?!")
Wormshit, is used to describe a lowlife type person.
Catshit, is always something that you step in.
"Piece of shit" is used to describe something that doesn't perform as expected. Eg. "That salesman was feeding you shit, this car is a piece of shit."
"The Shit" is used to describe something good. "That salesman doesn't know his shit, this car is The Shit!"
"No shit!" means, "Of course, you are correct."