General Happiness:
* On cloud nine: Extremely happy.
* Walking on air: Feeling very happy and lighthearted.
* Over the moon: Extremely happy and excited.
* In seventh heaven: Experiencing great happiness and joy.
* Tickled pink: Very pleased and delighted.
* In high spirits: Feeling cheerful and positive.
* Full of the joys of spring: Feeling lively and happy.
* Like a dog with two tails: Extremely happy and excited.
Specific Happiness:
* Happy as Larry: Extremely happy, often used in a lighthearted way.
* Happy as a clam: Feeling very content and relaxed.
* Happy as a pig in mud: Extremely happy and enjoying something to the fullest.
* Grinning from ear to ear: Smiling broadly due to happiness.
* A smile as wide as the Grand Canyon: Smiling very widely, often because of joy.
* The happiest day of [someone's] life: A day filled with immense joy and happiness.
Happiness in Relationship:
* Living happily ever after: A state of continual happiness and fulfillment in a relationship.
* Made for each other: Perfectly suited as partners and destined for happiness together.
Not Happy:
* Not a happy bunny: Feeling unhappy or irritated.
* Not a happy camper: Unhappy and dissatisfied.
* Not happy with: Expressing disapproval or dissatisfaction.
These are just a few examples, and the specific idiom used can depend on the context.