So...

At dinner tonight my sister mentioned that it bothers her when people tack the conjunction 'so' onto the end of a sentence and trail off. This 'so' is very common, I believe, especially when the omitted material is already in the discourse context.

A: He got into a car crash.
B: What? What happened?
A: He was drinking, so...

It occurred to me that this is very similar to the Japanese practice of adding から to a sentence. I explained how it makes perfect sense to have such a construction, and that it's perfectly natural, and she agreed and admitted to using it herself. But it still bothers me, she said. I got really frustrated, but finally I just said mu.　Well not really, I kept trying to argue with her, so...