Poppicat, being young and single you will go through many day and night dreaming about total strangers.
Once you start leading regular sex live those dreams may subside significantly and be associated with your actual experiences. At least you will not be missing your train station that often.
Dreaming is fun, enjoy it, but be cautious when chatting up strangers. Going back to the their place in your dreams may be a turn on, but if for real may turn into a missing person investigation...
How's France doing these days?