Situation one:
German class. The seat in front of me has some noticeable red streaks that looks like a little bit of blood that someone tried to wipe off. Sat there for like a week >_<
Biology class. I see a chair sitting in front of the class covered in red. I heard a student in the class graffiti-ing the tables, but this chair might've been BLOODY. *facepalm*

Some people just can't be sanitary, can they?