I have one of those colds that I like to think of as a Cú Chulainn flu.
Your body comes to you in the morning, with oracular prescience, and says to you: Listen, you're sick. You can either stay home like a sensible person and rest up, whereupon you will live a long and happy life. Or, you can not only keep to your regular schedule, but take on a whole bunch of extra stuff that sounds like a good idea, and you'll go out in a blaze of glory, and be unable to get out of bed for a week.
Guess I'm going skiing today, then.