how about " what's up"? hehe....

it's their way to start a conversation, but very annoying when you don't have anything to say.

要是真是不好,就说 i am OK, 或者 i am just OK.

I've heard different answerings like "I'm peachy", "Just hanging there", or "Pretty good, and yourself?". Depending on the relationship and whether you want to continue the conversation, you can create much variety on your answer.

俺都麻木了，被问得。

Yeah, when you are not that fine, say so. But of course they may continue to ask what happened and your stories can begin.

"good" is my favorite response, or "not bad", "tired", "busy"... I'm getting used to it now. For "what's up", my response normally is "nothing" or "nothing much".

我听说的是即便不好，也要说好。因为没人想听你诉苦