This is a true story. It just happened to me.
Step #1- pull up in the driveway from doing errands and see a gorgeous butterfly on a bush by the front door.
Step #2- run in the house to grab your camera.
Step #3- forget that there's a macro lens still on your camera.
Step #4- take the lens cap off inside.
Step #5- go outside and have your lens immediately fog over because of the change in temperature and humidity.
Step #6- attempt to take a photo of the butterfly.