A piece of garbage
A piece of garbage is someone who can't even do simple things right. They're like a broken toaster that still won't work.
My friend is a piece of garbage. He forgot his own birthday and still said I was annoying.
That guy is a piece of garbage. He fell off a bike and still tried to flirt with my mom.
My dog is a piece of garbage. He barked at the mailman and ate my shoes.