A big children's charity has asked 30,000 children what makes them happy - and unhappy.
Topping the list of unhappiness is 'not getting on with my family', but moving house and money problems also make children feel sad.
The Children's Society reckons half a million children in the UK could be unhappy.
But experts at the charity say they've also worked out what will make kids happy. Some of them are things that adults might have more control over.
The charity's six ways to be sure of growing up happy are:
- The chance to learn
- A positive view of yourself
- Important experiences
- Positive relationships with family and friends
- A safe home life
- Positive activities
We asked you what you think...
"Cooking makes me happy as does doing exercise and having friends round at my house! I like to go on holiday, my computer and t.v too! Sad movies like Marley and Me, going to school and being told what do by my mum makes me unhappy!"
Helen, 13, Wiltshire, England
"Going to school makes me happy and so does going on holiday to Turkey! But I don't like spiders... they make me unhappy!"
Holly, 13, Wiltshire, England
"What makes me happy: playing my flute, going to drama, going on holiday with my family to Scotland and Cornwall and stroking my cats. What makes me unhappy: cruelty to animals, school, war and arguments with my family."
Joanne, 11, Chepstow, Wales
"It makes me happy when I watch funny programs on TV with my friends, and sad when I see a sad animal."
Poppy, 11, Portsmouth, England
"It makes me happy when I am with my family, friends and pets. They mean a lot to me and are a big part of my life. It also makes me happy when I am on holiday in a hot country, as Scotland is freezing! I am sad when any member of my family gets ill or if I fall out with my friends."
Neve, 10, Edinburgh, Scotland
"When I fall out with friends and family that makes me sad. Going on holiday makes me happy because it is like having a break from the real world."
Annabelle, 9, West Midlands, England
"I am happy when I'm watching my favourite shows on TV!"
Lola, 12, Plymouth, England
"I'm happy when I'm with my friends and family, watching my favourite TV. shows, reading, playing my French horn and when there are good lessons at school. I am unhappy when my brother strops and when I have annoying teachers."
Maddie, 11, Norfolk, England
"I'm happy when I do well in school."
Precious, 11, Reading, England
"When I listen to music it really cheers me up and when I achieve something I feel on top of the world."
Dave, 10, Blackburn, England
"My best friends make me happy because they look out for me and they hang out with me."
Ivan, 10 London, England
"I am happy when I play my ukulele and get the chords right. I am sad when I get into trouble!"
Anna, 13, London, England
"I'm happy when I do my art. What makes me unhappy is when is I fall out with my friends."
Bryanna, 9, Ireland
"My brother has a very bad disability and he can't talk or walk or eat anything on his own. So when he is happy that makes me feel happy."
Florence, 12, Gloucestershire, England
"I feel unhappy when my parents have arguments and I hate it when my brother and dad smoke. It makes me feel like screaming at them! I feel happy when I stay at my uncle's and aunt's because they hate smoking and yelling. They always make me feel welcome!"
Hetty, 9, Kent, England
"My favourite TV programs and chocolate and hugs make me happy."
Destiny, 13, Oxfordshire, England
"I'm happy when I'm trying out something adventurous or being on a ride when you get wet or go fast. I'm unhappy when I'm lonely, bored or just starting French (it's so boring)."
Emily, 10, Cheltenham, England
"I feel happy when I'm at school and I'm passing my tests and getting a good education."
Brad, 10, Portsmouth, England
"It makes me happy to look at my fish because they calm me down and make me feel relaxed."
Karishma, 12, Surrey, England
"I really like hanging out with my family and friends. I am also BIG into swimming and my goal is to become an Olympic swimmer! That would definitely make me happy!"
Lowri, 10, England
"I am happy when I can go MAD with my friends!"
Jessica, 8, Wiltshire, England
"My teddy Milly makes me happy, because I like to cuddle her when i go to bed."
Milly, 8, Wiltshire, England
"This is what makes me happy: spending time with family, pets and friends, playing on guitar, school, watching my favourite films and playing sports like basketball and football. This is what makes me unhappy: Problems at school and home, bad treating of animals, and homework."
Joanna, 13, Belfast, Northern Ireland
"Spending time with time with my friends, eating junk food and shopping with friends makes me happy."
Aila, 12, Belfast, Northern Ireland
"What makes me happy is spending time with my family and friends, and going out shopping."
Courtney, 12, Belfast, Northern Ireland
"What makes me happy is when I can spend quality time with the ones I adore."
Claire, 13, Belfast, Northern Ireland
"The thing that makes me happy is when my friends and family are happy."
Nicole, 13, Belfast, Northern Ireland
"Just seeing my family alive and happy makes me happy."
Michael, 13, Belfast, Northern Ireland
"I'm happy when I'm playing football, golf, Gaelic or hurling."
Conall, 13, Belfast, Northern Ireland
"I am happy when I'm helping people at school and at home."
Filip, 12, Belfast, Northern Ireland
"School makes me sad and being outside makes me happy."
James, 12, Belfast, Northern Ireland
"I am sad when I'm in school."
Gary, 13, Belfast, Northern Ireland
"I am happy when I am with family that I love and cherish. I love summer days and going to the park. My friends and family are very important to me and play a big part in my life."
Mia, 12, Belfast, Northern Ireland
"Things that make us happy: spending time outdoors, reading and enjoying good books, arts and crafts, or celebrating special occasions."
Year 7M, Ages 11-12, London, England
"I think that children are happy when they get to do once in a lifetime opportunities such as trips, holidays, game consoles and laptops."
Luke, 11, Merseyside, England
"We feel unhappy when: My brother steals my toys, my sister teases me, I'm on my own at school, I lose at football, someone won't play with me. We feel happy when: All my friends are playing nicely, other people listen, I play with my friends, someone asks if they can play with me, getting presents."
Class 3D, 7-8 year olds, Kingsbury Green Primary School, London, England
"We are a class of 12 and 13 year olds who go to a secondary school in Stockton on Tees. We took a survey, and discovered that 77% of our class consider themselves to be 'happy'. We think one thing that would make us happier would be if we were able to play out safely with our friends more often. Some of us would also appreciate more pocket money so that we can buy more sweets and crisps. We would also be happy if some of our peers were less judgmental about our choices and appearance. Sometimes we would also like some of our teachers to have more patience with us."
Class 8GN, 12 to 13, Stockton-on-Tees, England
"Spending time with my favourite pony, Kimberly, makes me happy."
Jessica, 7, Warrington, England
"It makes me unhappy when I fall out with my friends."
Beth, 12, Swindon, England
"My friends and family keep me happy, and so does my school!"
Nicole, 10, Powys, Wales
"I don't like it when I have to move house. What makes me happy is Candy, my hamster."
Carys, 8, Cambridgeshire, England
"What makes me happy is being with my family. What makes me unhappy is moving from my house."
Izaac, 11, Cambridgeshire, England
"Pressure of work or presentations at school make me unhappy."
Emily, 12, Redditch, England
"When my friends tell me something funny it makes me happy."
Ruby, 8, London, England
"Having good friends, a good football team that wins loads, and a very good school makes me happy."
Josh, 10, Suffolk, England
"What makes me happy is going to the circus, the clown makes me laugh."
Savannah, 9, West Yorkshire, England
"My family make me really happy, and so does my cat."
Anna, 7, London, England
"What makes me happy is going to school and seeing all my friends. I'm happy when I go bike riding and horse riding."
Amelia, 8, Southampton, England
"Falling out with close friends make me really unhappy, also, being accused of something I didn't do makes me really unhappy."
Jess, 10, Buckinghamshire, England
"I'm happy when my family are cheerful."
Domenic, 13, West Sussex, England
"Seeing my friends before going on the school bus makes me happy."
Vira, 12, Cambridge, England
"I am unhappy when I get too much homework. Also, I hate it when my parents start arguing!"
Georgina, 11, Blackpool, England
"My laptop makes me happy."
Emerald, 13, Kent, England
"I feel happy when I have a time to watch TV and sleep after school."
Claudia, 14, Jakarta, Indonesia
"I am happy when I am having fun with my friends! It is loads of fun to have a giggle with your friends!"
Samantha, 10, Birmingham, England