couldn't happen to a nicer

serve someone right

To happen to someone who is thought to deserve it.

couldn't care less

To not care at all; to have no interest or concern; to be apathetic.

couldn't organise a piss-up in a brewery

Is unable even to organise a project that requires no planning; is inc…

couldn't carry a note in a bucket

Not musically talented, unable to sing.

couldn't stop a pig in a passage

To be bow-legged.

couldn't be more different

Two entities that have virtually nothing in common.