Pick At Meaning

(transitive, idiomatic) To pick on or repeatedly criticize (someone).

Example: 1853, Charles Dickens, Bleak House, ch. 45:
  Mr Vholes remained immovable, except that he secretly picked at one of the red pimples on his yellow face with his black glove.
1919, Henry B. Fuller, Bertram Cope's Year, ch. 4:
  He began to pick at the fussy fringe on the arm of his chair.
2009 Feb. 28, Laura M. Holson, "Putting a Bolder Face on Google," New York Times (retrieved 3 Aug 2015):
  Picking at a salad in a conference room at Google’s headquarters here, Ms. Mayer says she is vexed by how some perceive her.
1872, Louisa May Alcott, Work: A Story of Experience, ch. 9:
  "[N]oise and disrespect of no kind ain't pleasin' to him. His own folks behave becomin', but strangers go and act as they like. . . . Then we are picked at for their doin's."
1904, Margaret Sidney, Five Little Peppers and their Friends, ch. 15:
  "And I know she's my aunt, but she needn't pick at me all the time," she added defiantly.
2011 Oct. 14, Richard Barber, "Carol McGiffin: I've got a problem in the bedroom... Insomnia!," Daily Mail (UK) (retrieved 3 Aug 2015):
  "I get crabby and pick at him about stupid things that wouldn’t normally bother me."