One of the things I find so interesting about playing a game again years after I last played is how the information available about how the game works has advanced. The first time I played FFVII I played almost entirely in the dark. The second time I made liberal use of gamefaqs. This time around I am digging even deeper into the stuff on there. It may seem like I'm just finding new guides that already existed years ago, but no... There are guides with new information since I last played. For a game that's over 15 years old. That's pretty impressive I think!
At any rate, there's a scene near the end of the first disk of Final Fantasy VII where the main character chooses one of the other characters to go on an amusement park date. He'll choose between one of the three female characters or possibly the Mr T friend character. Not based on your choice at the time. Instead there are internal affection meters for each of the four characters that change as you make decisions throughout the plot. Be nice to someone and they like you more. Diss their world view and they like you less. Whoever ends up liking you the most when you get to the amusement park a second time goes on a date with the main character. The odds are stacked very heavily in Aeris's favour. It seems plausible that Tifa might get chosen if you're actively rude to Aeris at every turn but without really trying hard it's very unlikely to end up with Yuffie or Barret. I'm pretty sure I ended up with Aeris the first time I played and Tifa the second time. The second time I was trying to get Barret and failed because of faulty info in the guide I was reading...
You see, it turns out the game actually tracks two affection values for each character. One is used for the date, the other is used for nothing at all. But the first guy who took a hex editor to the game didn't figure that out. He just saw that some numbers were going up when you did all kinds of weird things so the first guide I read talked about doing crazy things. Like having Cloud attack Aeris in combat or using healing spells on Barret. Doing those things would adjust some internal numbers, but it wouldn't actually do anything.
It looks like there's a guide that got updated in 2009 that dug even deeper and worked that little difference out. I'm currently angling my way to meet up with Yuffie. I actually had to reset the game and replay about an hour or so because I forgot to recruit Yuffie in time to give her a tranquilizer on the boat for 4 affection. I messed up the meeting with the fort condor guys but I think I didn't have Aeris or Tifa in my party at all when I went in so I'm hoping it won't be too bad.