[bayonetz]

It's a mental model thing. Speaking freely (and probably self-disclosing along the way) is usually a sign of getting/being close. They see that behavior and think if they exhibited it, that's what it would mean. Which I think is a great example of how there are different "types" whether it be personality types, attachment types, what have you. Once you recognize there are types and that to a first approximation there are a finite, manageable amount of different types, you can learn how they differ and not get trapped by mistaking your mental model for everyone else's mental model. It seems obvious yet people seem to repeatedly make this same mistake as demonstrated by OPs experience.