I was listening to "Un día normal" by Juanes and the chorus is:
Porque nunca sabes lo que tienes;
Hasta que lo pierdes;
In English (my native language), using "one" is generally followed by a different verb ending than using "you." (Compare "you cook well" and "one cooks well.")
Here Juanes uses "no one" followed by the tú ending of the verb, when he could have easily used the third-person singular form.
Was his choice grammatically correct, or was it a bend of the rules to make the song feel more personal?