School dissatisfaction is an important commponent of the subjective well-being of adolescents associatited with "risky behaviour" like drug use, unprotected sex, norm violations and illegal behaviours. We extend the standard capital human model to joint human investment (education) and disinvestment (risky behaviour). Based on this model, we develop a general dynamic framework to analyse the preference formation of children and behavioural change at school. Once an educational norm is set by adults, children can rationally deviate from this norm, while staying at school, after experiencing bad surpass like a school failure. The same type of dynamic equation can be used on a sequence to predict education, satisfaction with school, and a hist risky behaviour. We test these assumptions with a unique panel data set on american adolescents attending middle or high school. School dissatisfaction is found to have a significant positive effect upon nine different types of risky behaviour.