1) Humidity damages HUD. My personal unit didn't have any problems, but this issue has appeared numerous times on the messages board ... steaminess can permanently damage the mirrored coating, leaving it permanently foggy. Since so much of Glass's appeal revolves around fitness, it's going to have to take the heat better.
3) Image problems. If I had known .... just Google "Google Glass" and you run into unsavory stores from evangelistic technophiles thrusting their cameras upon unwilling café-goers to adultery and drama at the top. None of this is consistent with my personal brand, the promotion of which was a key rationale for splurging on this dytopian Clockwork Orange future toy.
Still, Glass has been hella fun in some unexpected ways. I've met some interesting people I wouldn't have otherwise. All united by this expensive tool/toy. It's kind of like that fun blonde you know you shouldn't date. Maybe she's a little too fun. Then the humidity wrecks her hair. And she breaks down crying. Still tempting though.