I've had roommates that used my computer to look at porn. I wouldn't have been too pissed about it, only they have no idea how to look at porn. They click on any ad that looks interesting to them, and as a result my machine was constantly under attack by trojans and other nasty things. But that was years ago so...
My brother-in-law has a similar mentality when it comes to electronics. Actually, anything he doesn't know about, really. He is easily intimidated, and tries to hard to make people like him. As a result, if I say something about, say, electronics, which he knows nothing about. He feels the need to prove that he is just as knowledgeable and attempts to give his input, which more often than not makes no sense, and is usually pulled directly from his ass. Example:
Me:
"Woo! Fallout 3 comes out next month, I can't wait!"
Him:
"Oh that game? I heard it sucks."
Me:
"Really? Interesting. Where did you get such insightful information?"
Him:
"I heard it from a guy."
