R-E-S-P-E-C-T

Here's the deal my roomate and I have been pretty close friends since 6th grade, but their are some things that he does that really tick me off. One of the few issues I've had with him are over my computer chair. Why you ask, because I spent 300 dollars on this chair and we have been through a lot. I put up with him and his girlfriend on a daily basis. How do you ask? Lets just put it this way every day when I try to sleep it sounds and feels like an earthquake is going on above me. I told my roomate their is one thing off limits, and I told him this because he had already ticked me off by being in it before. I know what you're thinking this guy is a real jerk because he doesn't want his friend sitting in his chair, but it's not like that at all. He sits in my chair with his girlfriend on his lap which bugged me, so I confronted him about it and told him not to do so. Well today I finished my chemistry test early and headed home. Then I opened my door to find my roomate in my chair with his girlfriend completely stratling him. I got instantly pissed and push came to shove and I haven't seen my roomate all day. Sometimes I wish everybody was raised like me, and taught respect for other people's property and feelings. I mean come on isn't it common sense?