Deadweight loss of taxation.

In each of these cases, the quantity of labor supplied responds to the wage (the
price of labor). Thus, the decisions of these workers are distorted when their labor
earnings are taxed. Labor taxes encourage workers to work fewer hours,
second earners to stay at home, the elderly to retire early, and the unscrupulous
to enter the underground economy.
These two views of labor taxation persist to this day. Indeed, whenever you
see two political candidates debating whether the government should provide
more services or reduce the tax burden, keep in mind that part of the disagreement
may rest on different views about the elasticity of labor supply and the
deadweight loss of taxation.