"With Google Glass, it may look like you're listening to the person in front of you, but you could actually be watching a movie or looking up sports stats."
Unfortunately the problem is the opposite and more offensive. It's very obvious if you're having a conversation with someone while they're using Glass while looking at you from their eye movements, and it makes the user look really weird ignoring any fashion issues. I found the experience quite a bit more offensive than having someone reading emails on their laptop while you talked to them. Unlike the laptop case, with glass you get a very clear direct view of their eyes as they scan whatever glass is showing them, while there is the obvious false pretense of giving you their full attention.
I think one of the big problems with glass was that they picked the wrong sort of people to be early public users that then set the tone for the product. A process that ensured only super-enthusiastic users would bother applying is also the sort that would select for the least willing to notice how other people might find certain uses of it rude and annoying.