How do you stop feeling frustrated?

It could be a lack of sleep, or lack of pleasure, but sometimes when I'm at work, I get frustrated by this judgemental voice in my head that says things ought to be a different way.

Even though I know absolutes are unreasonable in most cases, I find it hard to shift out of that mode and make light of things. Eventually I get there, but I don't like having angry thoughts, and a clutching feeling in my core.
Anyone else experience that? Does it ever subside?