Yeah,just like "damn you".

The meaning of "奶奶的" is just like the meaning of "damn it".So we use it to express our anger.

哈哈，我觉得这类“问候对方祖宗”是中国特有的骂人的话。 如：你爷爷的！他奶奶的！我操你祖宗18代！你他妈的！

口语中表示抱怨的意思。没有骂人的意思，只是一句抱怨而已。通常是对着第三方，不是说话人和听话人的

It is exactely a like as "damn shit" "fuckof" "fucking you" yeah, it is the sam usage, you can use with close friends, or with s.o you don't like.