Chie's not a logical person, and everyone knows it. So when it comes to decisions where she needs to make sure she won't regret it in the future-- well, er, that isn't going to happen anytime soon.
All of the real decisions she's made for herself haven't ended up as perfectly as she wanted them to in the past, so she doesn't want to screw up again - she's scared that it'll hurt her friends and anyone else she holds dear. It frustrates her because she doesn't know what to do most of the time. She tends to leave the important things for everyone else and then choose to agree or disagree.
At the very least, the only good decisions she can make are the short term ones that affect her at that very second (but even then, her decisions are a bit sketchy). She's more of a person who takes things head on anyway.
Long story short, if you send her down a road with two different paths, she'll probably get frustrated because she doesn't know which one to choose.