pick on
US /pɪk ɑːn/
UK /pɪk ɑːn/

1.
prendersela con, tormentare
repeatedly single out (someone) for criticism or unkind treatment in a way perceived to be unfair or unjust
:
•
Why do you always pick on your little brother?
Perché te la prendi sempre con tuo fratello minore?
•
The older kids used to pick on him because he was small.
I bambini più grandi lo prendevano in giro perché era piccolo.