Environmental alteration

The screen on the device changes, and a new menu pops up, with a bit of text.

Please type in your wishes for environmental change.

You take a couple of moments to think. The description was rather vague, you´re not sure what exactly you can expect from this. You decide to make a careful test first. You type in the simple phrase:

All cars are blue. ****

And hit confirm. You get dizzy for a moment, then you feel alright again. As you look out the window, you cant believe your eyes. It worked. You uickly look at the device again, in disbelief. A new text appeared.

If you wish to undo a change, enter a wish to return said thing to the status quo.

You quickly type.

Return cars to the status quo.

Again, you feel dizzy, and again,a s you look out the window, you cant believe your eyes. The cars are colored again as they were before. Then you get a new idea. If this could affect objects...could it affect humans as well. Before you can change your mind, you type in:

Humans bow when they meet each other,

And indeed, as you look out the window, you see two people bowing to each other before beginning to chat.
You undo your changes. You feel dizzy, but not of the device. Thousand options run through your mind. What would you use this power for? Did it have any limits? And, most importantl, what should you change first?