NameIsRobertPaulson said:
Gladly.
Spoiler warning for those that care.
Cloud
Cloud is often described as an "Emo" despite there being little in the game to support that view, he spends much of the game as a wisecracking jerk that has a somewhat solitary attitude.
As the game progresses he comes to accept the help of those around him as he comes to trust and care for them.
He later discovers that he may not be who he thinks he is, sees one of the companions he cares deeply for die in front of him, gives the ultimate weapon over to the villain, is explicitly told that he isn't even a real person and then is completely mind raped by getting far too close to the life stream, he then spends some time in a coma, recovers comes out the other side of this trauma a stronger person and gets shit done.
The time he spends "being Emo" is less than an hour in a forty plus hour game, and it's fucking justified, I'd like to see you go through that and pull through.
Sephiroth
Another one whose world view is shattered, he discovers that he is in fact NOT human, at least not in the same way as everyone else, he was always distant from those around him but upon this revelation he completely seals himself away to study on his origins.
He spends several days with a massive pile of books filled with data about his creation, now tell me you'd be fine after that, he very rapidly falls in to insanity, seeking some reason to exist he hunts down Jenova.
He's not trying to destroy the world so much as he is looking for a reason to exist.
This makes Cloud and Sephie two sides of the same coin, they both discover that they are not who they think they are and they both break, Cloud came out of it deciding to find his own reason to go on, whereas Sephie began clutching at straws.
Aeris
"I'll rip 'em off!", should suffice here but I'll carry on, she's really more of a tough spunky type, people trying to kidnap her daily? She shrugs it off.
She's flirty, and constantly pro-active, Tough guy with a giant sword? Better walk him home, he might get hurt.
Tough guys friend in a cage being transported to a known pervert? let's get her out, plus this'll be a great chance to see what that guy would look like in a dress!
Stuck out side a "gentlemen's club" waiting? a great chance to con some poor sods out of their money by flirting with them and selling flowers at an exorbitant rate.
Every time she has a problem she puts it forward, she talks bluntly about what she plans to do even if it could be really fucking dangerous, and she is very willing to call Cloud out on his bullshit.
Tifa
Yes she's the tough girl but she is incredibly shy and quiet, she tends to keep her opinions to herself and she envies Aeris' outgoing and confidant nature, She wants to tell Cloud about how his memories are off but is afraid of how he'll react, she keeps quiet about her feelings out of fear of rejection, though she lays down a good few hints she can't bring herself to say it outright.
Overall most Final Fantasy charecters get similar treatment from both fans and non-fans alioke, they nearly alway ignore their actual charecterization, in favour of their own opinion of it.