There may be something about your communication style (or pre-conceived notions people have of you) that leads people to think they need to clarify things that you find obvious. Lets try this:
Me: "You're blocking my car"
You: "OK"
Me: "I'm leaving at 2PM so you'll need to move it before then"
Oops, I just over-explained. Instead of OK, you say:
"Got it, I'll move my car before you need to leave at 2"
I now know you understood your action item (and deadline) and there's no need for me to clarify. Once you do that a few times I have confidence that if I say something with an implicit action item for you, you'll get it and we can lapse into a more concise communication style.
There are may also be other issues of social expectation at play here. Are you by chance from a different culture than the people you're talking about? People from the East Coast of the US tend to be more abrupt (what do you want?). People on the west coast more round-about (Is there any food or beverage I can get you?). People communicating across cultures tend to over-explain in order to get confirmation that they've been understood (and for the gender differences read the fabulous article "Men Explain things to me"). I know that when traveling in India my understanding of what was implicit was wildly inaccurate. I got to the point where I needed explicit confirmation before I was confident that we'd communicated. The people there could have prevented mutually frustrating repetition by telling me their understanding of the implications of our conversation.
