Observable Traits are the Result of Gene and Environment Interactions
Your observable traits, also known as your phenotypes, result from interactions between your genes and the environment. Differences in some phenotypes, like height, are determined mostly by genes. If you have short parents and grandparents, you probably don't tower over your peers, though environmental factors like a healthy diet might give you a little lift. The influence of genes on other traits, such as your personality, is less well understood.