[mrpeek]

I have always wondered about this. I would imagine that when two people first meet, they would of course use polite form, like -masu and desu after their sentences. So when does the transition from polite to plain form happen? Does one of them just determines that "we are now close enough" and start talking to plain form? And then the second person follows suit? Or is it just depending on the person, like, maybe younger people are more casual so they will already start off using plain form (at least with people that are around their age)?