I think I came up with this term myself. Entropy in the world tends to grow, unless there's organizing force. Houses and roads fall into disrepair unless maintained.
Similar thing happens on the personal scale.
Things that I put off seem to get harder to get back to as days go by. The fears that I haven't confronted grow stronger. The guilt over losing touch with a loved one increases. Thus, the name Personal Entropy. It is the part of me that works against my best interest.