Why would my wife do something like this? Should I be concerned for my safety?

I have a garden in the yard. I grow a myriad of things, including herbs. I don't want my wife using my herbs, so I told her that they were poisonous and that she shouldn't use them as seasoning. (They aren't, I just don't want to share them with her. There aren't many of them, and they're hard to grow.) In any case, I told her to make me lunch the other day, and when I went to eat my sandwich, the bread fell off. Under it, a saw loads and loads of my herbs. Why would she do this?