You know how you can go on a date with Barret when you ger co Kalm? Well, I can't. It pisses me off! I've done everything else in that mother fuck'n game and I can't do this? I've read shit on how, but it don't work. GOD DAMMIT!!
The same way that you're nice to barret, just do the opposite. Just be especially mean to Aeris and especially nice to barret, and you should end up on his date.
Ok, don't have aeris in your party unless you have to, in the beginning win the soldiers are chasing aeris, push the wrong barrels(this makes her REALLY mad,) and be nice to barret. Try to be as mean to everyone else as you can.