Why do the Americans wash their teeth before breakfast? Well, I've seen it in many films. I brush my teeth after each meal...

I think the Europeans do the same too!
Its just a habit I have to wash my teeth as soon as I wake up it's the first thing I do, and before I go to bed!

I'm not sure it's just an american thing. It may have to do with facing your loved one with the dreaded morning breath.

I brush my teeth as soon as I get up in the morning. I go for a morning walk long before I have my breakfast. I wouldn't dream of talking to someone before I got rid of morning breath.

Because few things taste worse combined than toothpaste and orange juice. :p :)

Because for most it's a convenient time to do it, while they're shaving, combing their hair, etc. However, as your post suggests, it is in fact far more logical to brush after a meal rather than before.

For me, my mouth feels like it needs to be freshened up before I join the living world. ( makes my breath better)

Thank you very much for your answers! :)