For the first several years of graduate school, I was a relatively high profile person. I attended job talks, professional discussions, and social gatherings, held elected office in various departmental organizations, etc. After a few years pretty much all of the faculty could connect my face to my name and even people not in my field would ask me in the elevator what I'd thought of the latest faculty search possibilities. This was all terribly flattering as well sa professionally educational.
Then I cut off most of my hair and sequestered myself with my books and computer, visiting campus only when essential. Today was one of those days. Its very amusing high points:
1) while checking my e-mail in the graduate student lounge whisper to each other "who do you suppose she is? She looks too old to be a graduate student, but she's not dressed like a prof. Is she even in our department?"
2) hearing two other graduate students discuss #3 in the elevator
3) unintentionally eavesdropping on two history faculty members discussing the relative merits of a third
4) again, very unintentionally listening to two other faculty members discuss which graduate students they felt should be expelled from the program. (Fortunately my name was not among them.)
Now, the first two stories were amusing but not surprising. At my stage of the game I have next to no contact with first years and while they might possibly have heard my name, they've no reason to know what I look like.
The latter two instances left me puzzled as to an appropriate reaction, other than walking away, which I couldn't. (Long story) None of these faculty are in my field, and I'm reasonably sure that I've never exchanged more than a "good morning" with one of them. The other three surprised me - not only that they would have such discussions in a public place, but that none of them recognized me as a grad student, even if they'd forgotten my name.