Mommy Star

When Simon Cowell signed Britney Spears to a contract to be a mentor on X-Factor, he, most likely, rightly assumed he'd be getting the pop superstar/legend that's sold 60 million albums (give or take) in the US. However, he, maybe not so surprisingly, ended up with Britney the Mother.
It would have made sense to assume that Britney, being the Queen of Pop, would have expected everyone to be as amazing as she is and never settle for less, to even be overtly critical of her own group. But it's really been the opposite. Britney never said one negative comment about any of her teens the entire show. No matter how poorly they performed or how negative the other judges were, every comment from Britney stayed positive and included such lines as, "I'm so proud of you" and "That was amazing."
When you think about it, what she said was no different than what any mother tells their young children. No matter how unrecognizable their drawing is, no matter how many times they struck out, no matter how bad whatever you let them cook tastes, you always tell them whatever they did was amazing. It's almost like a reflex.
Remember when Simon said something unflattering about Beatrice Miller? Britney quickly defended her by saying she had more talent in her pinky than all of Simon's groups combined. The comeback was clearly ridiculous, but it's what a mother says when her baby is insulted. Plus, Beatrice's huge smile showed how much she appreciated Britney standing up for her.
Would it have been more fun if Britney were more critical, more demanding? Maybe, maybe not. But it wouldn't have felt as real. I'm sure she spends most of her day telling her sons something that did was amazing. It's probably much more natural for her than sitting on some imaginary throne that her fans love to pretend she sits on judging people.
None of Britney's teens won X-Factor, but she was clearly the best mentor. The top 10 consisted of four of Britney's acts. She took Carly Rose to the finals. All the while, she kept a positive attitude. Some people hated her stock quotes. But this is what mom's do, they repeat stuff. Britney just did what she's been doing for the last seven years.
Perhaps Simon is secretly disappointed in Britney's performance. But this is who she is now. She's a mother first and you can't just turn those instincts off. She's not mean, and she probably never will be.