happy as a pig in mud

couldn't stop a pig in a passage

To be bow-legged.

drag through the mud

To tarnish or spoil enough so that something or someone is no longer respectable.

happy as a pig in shit

Extremely happy; obviously satisfied and carefree.

happy chappy

A person, usually a young boy or teenager, who is particularly happy.

happy landings

Successful outcome or outcomes.

happy medium

A balanced position between two opposite extremes.

happy panda

A person who is happy and contented.

happy place

A mental visualization of a pleasant location, performed in order to avoid thinking or dealing with something unpleasant or painful.