지만

But... (often left hanging)

Concedes something before the counterpoint: it might look like huge portions, but the bowls are tiny; I've been to so many buffets overseas, but...; I had a hard time with the ring size, but. In these lines it very often ends the sentence and leaves the 'but' dangling, which is a soft way of implying the rest without saying it. It works in any register — polite, formal or plain — because the politeness sits on the verb before it.