What makes it dangerous? Is it because asking these questions may lead us to answers that God doesn't like, or because God doesn't even want us to ask questions in the first place?
Second guessing is not asking questions ... God actually encourages us to do that but even in this there are guidelines to offer you protection from deception. Satan is smarter than any human and can deceive in astonishing ways. Second guessing is ‘telling God how He should do to do it better’, and the foolishness of that is immediately evident when you realize we are so very limited in our input data.