The image of stove comes to mind immediately. God is saying, "Right now your passion and desire for me is about a four or five (out of ten). Is that good enough for you? Because it is not good enough for me. I didn't create you to be just a four or five— turn up the heat. I want more for you and I want more from you, don't settle for less." I think that's why I love this passage. It is an invitation. God is inviting me into a deeper, more intimate, more passionate relationship with him. God wants my inner life to boil with affection and desire for him.
The reality is that we all boil inside for something. There is something in our lives that is getting our passion, that is on the front burner. It might be work, it might be family, it might be a significant relationship, it might be wealth (like it was for the Laodiceans), or it might even be ministry. Something is on the front burner of our lives, receiving all of the heat of our passions and desires that only God deserves. Our challenge is to take the time and space to figure out just what that is, to name it, and to return (repent) him to his rightful place on the front burner of our lives.