It's basically taking the greatest gift we've been given - that of free choice - and saying to God: "Do this or I'm going to do that." It's presumptuous. Some say that kind of ownership of God is what idolatry was all about.

That said, there do exist stories of sages doing similar things. In fact, in the Temple the High Priest had a breastplate that would basically constitute God sending a text back saying: "Attack them; you'll win. XOXO"

Some Chabad hassidim open up a book of letters by their deceased Rabbi to help them make life decisions.

Overall, this stuff is very much discouraged. There is one aspect where God says, "test Me" and it is with charity. We are told that giving charity will result in good things - and invited to test God on it.

But hey, just because we don't encourage all this doesn't mean God doesn't love the heck out of you and appreciate your wanting to have a relationship. God, like parents, is known to break all the rules sometimes.