Oh, Potter, you rotter, oh, what have you done,
You’re killing off students, you think it’s good fun —

Oh, most think he's barking, the potty wee lad, but some are more kindly and think he's just sad, but Peevesy knows better and says that he's mad.

Loony, Loopy Lupin.

Which way did they go, Peeves?" Filch was saying. "Quick, tell me."
"Say 'please.'"
"Don't mess with me, Peeves, now where did they go?"
"Shan't say nothing if you don't say please," said Peeves in his annoying singsong voice.
"All right- PLEASE."
"NOTHING! Ha haaa! Told you I wouldn't say nothing if you didn't say please! Ha ha! Haaaaaa!" And they heard the sound of Peeves whooshing away and Filch cursing in rage.

Give her hell from us, Peeves."

And Peeves, whom Harry had never seen take an order from a student before, swept his belled hat from his head and sprang to a salute as Fred and George wheeled about to tumultuous applause from the students below and sped out of the open front doors into the glorious sunset.

Harry witnessed Professor McGonagall walking right past Peeves who was determinedly loosening a crystal chandelier and could have sworn he heard her tell the poltergeist out of the corner of her mouth, 'It unscrews the other way.