Apparently Simon Cowell would have rather had Britney Spears beating cars with umbrellas again on 'X Factor' instead of just, you know, showing up late once in a while.

The crankypants Brit wanted his own highly-paid Brit to be more entertaining and a bit more of a loose cannon on the struggling Fox show, but instead she was just sort of ... off.

"She acts like she has a different contract than everyone else," a source told The Daily News Confidenti@l. "She shows up late, she wanders around aimlessly and she is in her own world. She wasn't ready for this responsibility."

Spears apparently wasn't wild enough to draw in the huge ratings Cowell was hoping for, because the numbers for the second season of 'X Factor' were still pretty disappointing. Now many insiders say she won't be asked to return.

The 'Toxic' singer's behavior wasn't just bizarre when she was around Demi Lovato and Co., either. Apparently she showed signs of a decline in function on her Fantasy Twist perfume commercial set, too.

"First, she wanted the producers to fly Vanilla Ice in to duet with her, which was just weird," a source said of the bizarre shoot. "They called him and he wanted $500,000, so that wasn't going to work." (Hold up. Vanilla Ice still gets paid 500 large for an appearance?)

"Then, she demanded that exotic animals be flown in to be in the video and they had to tell her that that wasn't going to work for legal reasons and insurance reasons." We can see why they'd decline that demand. If someone unstable enough to request a Vanilla Ice duet wants to be around deadly animals, we can't see that ending well.

And it wasn't just Brit's behavior that was ugly -- so were her makeup jobs, because she didn't trust the professionals.

"She wanted to do her own makeup and when she would get it done, she would just mess it up on top of what they did," the source tattled.

The spiller also reminded everyone that while Spears is engaged to manager and co-conservator Jason Trawick, they still haven't set a date -- leading many to believe that they're on the outs.

Still, we're willing to give that sitch the benefit of the doubt. We don't think he'd walk away from a cash cow like Spears, and considering how out of it she was during 'X Factor' filming, they may have simply wanted to wait til her $15 million season was up to start planning the wedding.

After all, that kind of jack can buy a lot of PBR and Funyuns for the reception.

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