Distracted

If you ask Hubs to make you some french toast, he will go into the kitchen and turn the light on.

Then he will notice there are several light bulbs that have burned out, so he will change them.

Then he will wonder if any other light bulbs need to be changed.

So he changes all the light bulbs in the house.

He goes back in the kitchen, and can't remember why he turned the lights on in the first place.