You become like what you worship. God has woven this movement into the fabric of the world. Israel saw this two-edged truth throughout her history, and the Psalmist summarized the negative truth of what they learned (or didn’t learn) in Psalm 115:4-8. The positive side of this statement is that if you worship Father, Son, and Holy Spirit, you will be remade into the image of the Triune God, the image you were created to bear; the image that sin had shattered.
But it isn’t enough to pick the right God, and then proceed to worship Him in whatever way you choose. Not only do you become like what you worship, but you become how you worship. If your worship is casual, lazy, and half-hearted, you will become an ever more casual, lazy, and half-hearted person, because worship changes you. Even if you never get struck down by a bolt of lightning from heaven, what kind of person are you becoming because of your worship? So dress differently, sit up straight, sing gladly, and listen with care, not for the sake of “good manners”, but in order to become like God.