ok, here is an example of a fantasy style of character interaction.

In ff7 when Aeris and Cloud meet it basically doesn't go much further than the lines of girl meets heroic boy, girl likes heroic boy, girl and heroic boy go off to fight evil together.

But for instance in xenogears when Fei and Elly meet there is much more of a realistic feeling to what the problems the two people might face in real life. Girl and Boy meet, girl and boy do not hit it off right away, girl and boy's interaction with eachother is very affected by what is going on in their lives at the time. Both go through the growing pains of getting to know eachother.