You are the worst kind of person; you should not be on the face of this earth

An insult that is used to insult people.

= You're nothing.
However, 'you ain't shit' isn't necessarily an insult. You can comfort someone by saying that they are not shit.
You ain't shit vs. You are shit is definitely not the same. 'Ain't' is a general negation vernacular term.

you just trashy,ain't nothing but a bum,creep,loser,coward,waste,etc
or someone who can't do nothin,but eating,playing and sleeping

An awesome term to use when someone is being, in fact, a little shit.

Someone who is being annoying but funny!

you really suck at a sport or game or anything you do

what you say when you get attacked by a ghost on pac man