I'd always heard and expressed that as
Sh** Happens.
(Not as philosophical or PC, but it do get the point across, don't it?)
That's another way of expressing it.
Here's another way of going at it. Some old guy on my job used to say this, as a way of not stressing.
"Don't sweat the small Sh*t. And it's all small Sh*t."
Bagster
Or.... “Embrace the Suck”
(Sorry Charlie! Its not my thing, its a Desert Storm Thing!)