It's kind of strange to think the actors and actresses in movies and TV shows when acting, whether its an emotional scene or whatever, could be thinking about anything like, "Ooh I think I'll have chinese tonight" or "I can't wait for the weekend", amirite?

What? No.
To be a good actor one must be in character, therefore simply believing they are the character and thinking the character's thoughts. One cannot do a big emotional scene from another person's life while thinking about Chinese food and the personal life of a completely irrelevant person (the actor).

Thank you Nackiefoodle, I was going to say exactly that if someone hadn't already said it :)<3

You have to be in character when you are acting, especially ones in movies and TV shows. The Disney kids already suck without thinking about Chinese food.

Plus, if you were having an emotional scene in real life, would you not be responding to it, or thinking about random things in between?