Don't take it personally is an oft repeated platitude I hear repeated in the work environment. While I think it's unhealthy to take problems at work and things out of your control as personal affronts, I think a healthy dose of taking personal ownership of your work is "a good thing" (tm). I say this because the counterpoint to not taking things personally is not giving a damn and I think this is a far worse situation than folks who are personally invested and passionate about their work.
In my experience, the most successful folks I've interacted with take a very deep personal interest in their life's work. They are passionate, appropriately loyal, and care a great deal about the quality of the product or service they provide. Folks that punch the clock, point fingers, and skip home after their "8 (or so) hours of physical presence" are huge problem and all too often a key source of low quality work and cumbersome process. More dangerously this leads to a culture of "not my job" and causes folks who might otherwise be outstanding performers to ask themselves "why should I put forth any extra effort?" or "what's in it for me?".
So I amend the platitude and say this: Take personal ownership of your work, while I'm not about to spout phrases like "Arbeit Macht Frei", I DO think it is better if one approaches their work with a sense of ownership, responsibility, and a certain amount of pride in what they do for a living.