I've only recently started using Cortana in any meaningful way, but it has been doing one thing that is really annoying. It has been giving me travel tips based on travelling around by Transit instead of by car. The main one it reminds me of is getting home from the office when I am at the PI office and less often getting to that office from home (I spend a lot of time out on site with clients).
What's the problem you're wondering. The problem is that because it is using Transit, it tells me I have to leave work at 1320; or even worse that I need to leave home at 1400 on Saturday to get to the offic for 0700 Monday.
These messages have been popping up on my Windows Phone for a while and I have scoured the settings repeatedly looking for a way to fix it by changing the method of travel to car without success and had started thinking about switching off Coretana entirely.
Then the other day I had to get my laptop rebuilt (new OS installed after replacment of parts leading to jokes about the Laptop of Theseus) and activated Cortana. I found something called Notebook with lots of settings broken into areas.
To find Notebook, hit the Windows key and type Cortana. The third icon down on the side of the Start menu is Notebook: