Walking Through Doorways

I sent Barb a Facebook post about how as you get older you find that when you walk through a doorway into another room you forget why you were coming into that room and that it was caused by the doorway not you.  Barb said she didn't realize that it was because of doorway that that happened.  Today Barb came into the kitchen saying "The greatest thing I ever did ... " then she says "I forgot what I was going to say".  How could she forget "the greatest thing".