Remember, the government see's an 18 yr old as capable of voting for the entire nations future and stake, they see you as capable of signing your life away to fight in overseas wars and become a trained fighter, they see you as capable to control the deadliest creation man has ever made by yearly deaths (a car), they see you as responsible to live on your own, maintain a job, and pay your bills, they see you as qualified to get married, and have children, who you are completely responsible for, they see you as being qualified to travel around the world and out of the country alone, they see you as responsible for all your own actions in the eyes of the law.
But they dont see you as responsible enough to buy a cigarette, i hate smoking, but this is actually really retarded, might as well change the age for all the things I mentioned.
"But muh 21 drinking age" that's unique to the US mostly and it's a leftover of prohibition, almost every other developed nation allows drinking at 18, with some as low as 16.
