Mistaken Identity

Tonight at dinner, Brannon picked up David's phone and said, "Daddy you're 3" (which means that David is #3 on speed dial on my phone). David told him that since it was his phone that mommy was #3 on the speed dial. After giving David a confused look he decided to call mommy (even though I was sitting directly across the table from him). So he calls and I answer,
"Hey, Brannon."
"MeMe?"
Are you kidding me, I'm sitting across the table from him and he's watching me talk on the phone.
"No, it's mommy" We continued to talk for a few seconds and then I got off the phone.
A few minutes later he decided to call mommy again.
Ring, ring, ring.... (I decided not to answer this time)... voicemail.
"Mommy's not there. I think she's at work."
I really don't get it!