A lot of people disregard the creative aspect of programming, even if you're feeling great, some days creativity comes, some days it doesn't.
In the company I work for, which is horribly ran, a lot of the projects I work on have a bus factor of 1 - which is me. So, me taking a sick day, or even vacation can throw off one of the many arbitrary or poorly planned deadlines.
I haven't found a good answer to this, but I find it helps me to have a good routine such that no matter how dead tired or sick I am, I can engage the routine and get _something_ done.
In the company I work for, which is horribly ran, a lot of the projects I work on have a bus factor of 1 - which is me. So, me taking a sick day, or even vacation can throw off one of the many arbitrary or poorly planned deadlines.
I haven't found a good answer to this, but I find it helps me to have a good routine such that no matter how dead tired or sick I am, I can engage the routine and get _something_ done.