I also grew up in California too. That is how a lot of people actually talk there. I never really got into using "dude" as a catch all identifier myself though.

Yep.

Just like manana means tomorrow or in the morning. Just because the dictionary says it, doesn't make it so. I learned in Spain, that at least as it applies to someone taking care of something for you and they answer the question of when it'll be fixed, manana means, "You'll be lucky if it's in this lifetime, now fuck off and leave me alone. It's time for my siesta." Dude has a similar, generalized meaning, for which any dictionary entry will never do it justice.