When a girl immediately leaves in the morning from an f close, what exactly is this signifying?

Does it mean she wasn't as attracted to you in the morning?

Could it be she doesn't want to be seen as needy?

I've had one night stands with girls that stuck around for morning sex and sometimes breakfast. Other times they're out the door the second they wake up.

Anyone have any insights or experience on this? Or am I just reading too much into it?