Victimless crimes are those that allegedly don't affect other people. The three most common are gambling, prostitution, and drug use.
However, they do effect other people. Prostitution can break up a marriage, gambling losses effect the entire family, and many people resort to crime to support their drug habit.
I hear people say "it's my body and it should be my choice if I want to take drugs", but the problem is very few people can afford a drug habit. If you ever had your house burglarized by a drug addict looking for his next fix, you will agree there is no such thing as a victimless crime.
