Although it happens so often it should no longer be a surprise, it is nonetheless often surprising how stepping away from your desk and doing something totally

Although it happens so often it should no longer be a surprise, it is nonetheless often surprising how stepping away from your desk and doing something totally unrelated to the problem you're battling with or the bug you're tracking down - like watering plants, going for a walk, etc. - provides you with a solution in a few short minutes. That's why I often tell employees who are blocked on some problem or are visibly frustrated with a bug to just go do something else for a while. It's more of a waste of time to keep working at it, then to "slack" and quickly achieve a flash of inspiration.