Alchaholism actually IS genetic sometimes. Like, some Native Americans can have two beers, and get as drunk as if they'd had twelve.
Personality, alot of the time, isn't in genetics, its in the way the person's parents bring them up. If someone's parents don't like veggetables, and their parents never ate veggetables around them when that person was a baby, or at all, then that person will most likely NOT eat veggetables. But, if someone's parents eat veggetables around their children, from the start, than that person will most likely WILL at least eat veggetables.
Some things, like allergies or diseases, are, very genetic, depending on what they are. An entire family can have a fatal allergy to chocolate, because it was inherited via family lines/genetics.