1. Mickey: Mom, get me some milk, please.
Mother: Get it yourself.
Yes. The mother's reply is not very polite, even with the informal register. This is correct, because the mother is showing that she is annoyed by the child giving a request as an instruction.
2. Guest: It's hot today, isn't it?
Host: There's orange juice in the fridge if you like.
Yes. Here the guest might have been indirectly asking a drink, so the host offers some orange juice, but also does it rather indirectly, in case the guest was really just discussing the weather.
3. Mr Jones: Excuse me, could you pass me the salt, please?
Miss Wilson: Give it back afterwards, please.
No. Miss Wilson has given an order to a stranger, and this is not polite, even with "please" at the end. The reply should be more like "Could I have it back when you are finished, please?"
4. Sally: No, Billy, you can't use my bicycle.
Billy: Aw.. pretty please!
Yes. This is more common with children than adults. However, it is sometimes used as a joke when a person wants to beg for something unimportant (like a sweet) from a friend.
5. Mr Cooper: I'm going on holiday next month.
Mrs Greene: Well, make sure that you enjoy yourself.
Yes. Mrs Greene is not really giving an instruction, she is saying that she hopes Mr Cooper willl enjoy himself. In the same way, many people in the United States use "Have a nice day."
6. Boss: Get that done by Saturday, Harry.
Harry: I'm not sure that's possible.
Yes. Harry is being very polite, but he is saying that he will not do what the boss wants, because it is not possible to do it. He gives his refusal as a statement, so that it causes minimum offence. Harry should now explain why it is not possible.
7. Child: Mom, can I play with Jenny?
Mother: Don't make too much noise.
Yes. The mother has used the second part of a conditional sentence. The child understands that the first part (which was not spoken) is "Yes, you can play with Jenny ....".
8. Mike: Hold this, Joe.
Joe: I will hold this, Mike.
No. Joe's reply is too comprehensive, and it uses too many of Mikes words. All that is required is an a positive acknowledgement of the instruction/request; so use, "sure", or "ok", (for yes) or "hold on", "now now" (for no).