1. Legally buy pornography
2. Legally buy cigarettes
3. Legally gamble in Indian Casinos
4. Legally be concidered an adult
5. Be tried as an adult in a court of law
6. Be drafted for a war they don't believe in
... but still cannot buy alcohol.
Joey: Wow! I turned 21! I'm going to buy vodka and gamble in a real casino!
Billy: ... damn country.
Person 2: What did you do all day?
Person 1: I decided to enlist!
Person 2: ...stfu moron...