A: Simple. This happens:
(This is the Craftsman style bungalow next door we purchased in January. For other related posts, click on the tag Bungalow)

Kitchen Door
And this:

Bedroom Door
It appears that someone found a sale on green oil base paint and painted every door and baseboard in this house. Then, later, a super smart person painted flat latex paint over the oil base paint. Result? A house full of peeling paint for me to scrape off and start over! 🙂 YAY!

Kitchen Wall

Dining Room Arch

Butler's Pantry
I am scraping, sanding and peeling off the paint at present. When I am finished, I will cover the lovely green with white oil base paint.
Yay for me!
Andrea