No thanks.

This is an expression to use when someone offers you something, but you don't want it. Depending on how you say it, "No thanks" can sound angry, cheerful, or anything in between.

If you'd like to be more formal, you can say "No thank you."

(someone) is wired up

When you drink a lot of coffee or get really excited about something, you feel energetic in a nervous kind of way. We call this feeling "being wired up". 

You can use "wired up" to describe children:

Please don't give them any more candy. They're going to be wired up for the rest of the day.

(something) is (adjective) as it is

This phrase means something like "It's already bad, so don't make it even worse."

You use it like this:

A: You're so smart.

B: Why, thank you.

C: Don't tell her that. She already has a huge ego as it is.

Come on! Let's go! We're already late as it is.