Why Is Everybody Always Picking On Me?

Recently, we read The Ugly Duckling. In it, the little pretty yellow ducks pick on the large grey duckling. A new vocabulary word was born: pick. This week the word was a spelling word. We could use it both ways: to choose, to annoy. My students have attached themselves to this word.
Don't pick on me.
Quit picking on me.
Stop it! Don't pick on me again.
Miss April, she's picking on me.
Miss April, he's picking on me.
She picked on me first.

I love that they're learning English... but of course they would choose this word to use every three seconds!