Adult man can't buy a beer in USA

I’m 25 years old and currently I’m in USA, for a second time. I wanted to buy a pack of beer with my friend so we went to the liquor store. I knew that USA has strict rules about selling alcohol, so I’ve informed my friend to get his passport, I didn’t get mine. So, we got to the store, I’ve chosen Sam Adams Lager, friend of mine Sam Adams Octoberfest, but that’s not important. We came to the register and want to pay. Standard question about id, haha we’re prepared this time mister, I thought. But not, because seller wanted to see mine passport too. I had only driving license, I’ve explained. That’s not enough, said he:) OK, so I’m not taking my beers, but my friend want to buy some for him. No, he can’t. Why? Because he can give that beer to me, and I could drink it, and I’m not verified to be adult, 25 years old. So, no beer for tonight boys:)

That country is sometimes funny:)