Aw, but that still happens when you have a really well formed character. The only way around it is to get external plot twists that don't have much to do with the chara unless it's part of their history. That's another problem with not knowing your character well, there can be plot holes or slightly changed backstory from the beginning, though I try to make it work. :{
Also, if you ever need a hair color change for Lai, I'm sure someone there can be a good prankster.