Teaching is like painting a huge Victorian mansion. And you don’t actually have enough paint. And when you get to some sections of the house it turns out the wood is a little rotten or not ready for the paint. And about every hour some supervisor comes around and asks you to get down off the ladder and explain why you aren’t making faster progress. And some days the weather is terrible. So it takes all your art and skill and experience to do a job where the house still ends up looking good.