I am waiting...

…yet again, for the washing machine repairman. It’s all very existential. I was instructed that he would arrive between 10 am and 1 pm. I pointed out that this was ridiculous. I was told that there was no way they could give me a more precise estimate. Can anyone out there please explain to me exactly why the vagaries of washing machine repair/plumbing/what have you are so much more unpredictable than any other pursuit?