Maybe it's my Southern upbringing, but I always feel self-conscious wearing Glass in public. (Though, in full disclosure, I don't even like wearing prescription glasses in public, much less Google Glass. But that's another story.) Simply put, in my opinion, Google Glass would make even Justin Timberlake look like a super geek.
Plus, I'm aware that many people see Glass as creepy or intrusive, and it makes them uncomfortable. You could argue that this is because they don't understand Glass and that, eventually, they'll get used to it. Even so, as with any mobile device, consideration for others should play a role in when and where you wear Glass.
[ Related: Unique Uses for Google Glass, Demonstrated by Celebrities ]