My little brother says he's glad he doesn't have girls at school because he can't stand them. I politely informed him that in the workplace he would have to put up with girls. Very few professions provide single sex environments, so boys and girls need to learn to get along and work together. School prepares you for that.
What is it that makes you happy? For many people, life satisfaction will be influenced by many different factors, including their family and education. For those working in the education world, the aim of achieving happiness for pupils once they leave school and become adults may be a motivating factor, but rarely something they can focus on day-to-day...
Every child deserves to be given the same opportunities in life, the same chances to find their unique talent, to enjoy something for them, not because their parents push them into the limelight and then take credit for their achievements. As a parent we are biologically programmed to be proud of our children for any achievement.
This means that small tensions can easily escalate and in school this takes away from precious teaching time. The impact this has on their longer term attainment is that they may be unable to meet their full potential and can at times hold back other pupils in the class with the distractions they create.