NASCAR, though popular, isn't without its criticisms. One major complaint is the perception of monotony, as some find the idea of cars going around in circles for hours quite dull. Others argue that NASCAR isn't environmentally friendly due to the large amounts of fuel consumed during races. Safety concerns are also raised, with critics pointing out the high risk of crashes and injuries. Lastly, critics often question the lack of diversity among drivers, which they believe undermines the sport's overall appeal.