The downside of going on the facebook in public locations.

When you're stuck in the library, say, writing a paper due in 5 hours, sometimes you go on the facebook. And then you come back from the bathroom and you realise that the person sitting with the clearest view of your computer screen is a good friend of the person whose photos you just went through for the past 20 minutes, and... you really hope they were far enough away not to recognise the profile.