If you plan to do whatever you want when the mood strikes, you have plans. You absolutely do not have to explain what your plans are, and it really doesn't matter what you've done in the past. If the former best friend is trying to invite herself along and you don't want her to go with you, just say it won't be possible. If you're on the phone and she continues to bug you about it, you don't have to stay on the phone. There is a way to end a call without the other person's permission. You simply hang up. If she's there in person, just leave. Planning to sit in the park and read is a real plan. Planning to go shopping is a real plan. Planning to escape FBF is a real plan. You Have Plans!