taking the day off

"There are no days off for the novelist!" This was thundered at me and the rest of the audience at a writers' conference sometime in the '90s. "If you don't write every day, you're not a writer!" More thundering.
Please.
I'm all for regularity and routine--it really does help if you come back to the stuff you're writing frequently, if you don't leave it sit for days at a time and then when you go back you feel as if you don't know your characters. Once, when I'd taken a months-long hiatus, I tried writing my characters a letter because I felt so estranged. ( Did it work? kind of.)
So, yes, to write as often as you can is desirable, and even rewarding, and sometimes fun. But, oh thunderer, who is a big-name writer whose big name I won't mention, we do have lives, and sometimes we are sick and sometimes we have a child who is sick, or we have a job which is demanding, or maybe we just need some fun, we need to play hookey even from writing which we love and revere.
All of which I hope doesn't sound like an excuse, which it isn't, because I planned not to write today, and when you plan something, it's not a dereliction of duty.
Carl, I promise I'll be there tomorrow, and I'll help you get through the difficulties caused by the fact that someone wants you to come over to their house and exorcise their ghosts. We'll get through it together.