In the entire Naruto series, I could say these 2 kids had the worst childhood you could imagine....
Naruto had no parents and also had the tailed beast in him, parents of other kids don't even allow their kids to go close to him... Had a kind of life you could call 'hell', had a crush who does not even value him, even his teacher at some point didn't see him as anyone to reckon with, only one man and that was the third hokage(Hiruzen) talks with him....what dah fuck....
Gaara also just like Naruto was seen as a threat, though looks like Gaara kind of had some emotional or should I call it psychological problems that makes him go all unreasonable atimes, he was seen as a beast, he even hurt his own friends, even his dad, the precious kazekage tried killing him. Waooo
Little did they know that these 2 kids were going to become the heroes of the coming generation...
At some point Naruto and Gaara met and Naruto through his influence had a kind of way of making Gaara change his notion about life in general....... They both became best friends and decided to develop and work on themselves.....
Naruto was always optimistic, always saying he will become the hokage, they pushed through thick and thin and became successful national heroes......
They are both the Kage in their respective villages and well recognized and admired by all.
Personally I learnt from their lives that no matter what life is throwing at you at what ever point in life, you could work on yourself and become as great as you want to be.