Two days ago i was not asked for ID for buying one can of beer. Why today they did and told me that's the law, after i submitted it the female clerk look straight to my face to see if i was the person?

The law is a person must be at least 21 yrs old to purchase any alcohol. The store generally asks for I.D. in these situations because u may not look 21 yrs old and if u are 21 yrs old take there asking as a compliment. There just trying to follow the law. As far as them looking at your I.D. picture and then looking at you they just want to make sure your I.D. matches your face. There not messing with you. In fact they want to make your purchase. They just want to follow the rules and the law because they could be fined, lose the alcohol license, or both if they sell any alcohol to anyone under 21 yrs old whether that be 1 beer or a case of beer. Hoped that helped to explain your issue.

They just got the licence so sometimes they ask for iD and sometimes they don't... it depend of the Cashiers too...