I rarely consider email, or FB to have any interruption power at all. If I'm busy working on something, that is what I'm doing and that is what is important right now, not an email. I usually check email if I'm taking a break.

Unfortunately people waking to your cube has even more disruption power so I'm not sure why you preferred that option. Perhaps you were surrounded by people who used very careful judgement before calling or walking to someone's cube. But "Do you have a second" is not enough. You've already taken up three seconds, and now I have to respond, and to do that I have to guess whether what you have to say is important to me right now or not. My focus is gone. This is why I prefer to work remotely. I decide when to switch focus and for what reason.