The Aerosmith frontman - who joined the judging panel for the new season of the US TV talent search show - doesn't want to insult anyone or shatter their ambitions if they are not very good.
He admitted: "It's hard when you have a kid who's 15 years old, who's been watching 'American Idol' for the last 10 years. Some of them were awful. I just say something like, 'Did you bump your head on the way in?'
"I'm really not one for giving insults. They have a voice and I don't want them not singing to their kids when they grow up."
The 62-year-old rocker is not the only newcomer taking a place alongside Randy Jackson at the judging table this season.
Singer-and-actress Jennifer Lopez is also giving her verdict to aspiring pop hopefuls, and Steven is impressed with her attitude.
He told UsMagazine.com: "First and foremost, she's a lady and she's not afraid to show that at any given time.
"She's ridiculous. You know, she's exactly what I thought she'd be. She's street."