An individual whose life has no direction; typically unemployed "chav" who spends benefit monies on cars, cigarettes, fast food and the like. Refers to a distinct subculture of the human race; individuals who are Burdens on Society are often seen as wasters and drifters in life.
Alternativley, Burdens on Society could be seen as the morbidly obese sect. These are people who, through many years of poor nutrition and food abuse, have become perhaps three times the size of normal individuals. Thus, they are less healthy as a result - and later in life being a Burden on Society, specifically the NHS.
A recently emerging sect is the Smokers - lung-related illnesses such as lung cancer, brought on by smoking.
"Ugh, look at that fat woman. What a burden on society."
Old people, the mentally handicapped, cripples, etc.
Guy 1: My mom sits around all day doing nothing soaking up my hard earned tax dollars.
Guy 2: What a Burden on Society. Sorry, just sayin'.
Guy 1: Why should you apologize? She's my mom. I'm sorry.