It doesn’t happen often but every now and then you get into a situation in the three person block of seats when a space frees up and the person doesn’t move over. In the trains where it’s one large block of seats going from door to door that’s more normal, because you’re more likely to be moving close to another person. In this case it was an Asian girl watching something funny on her PSP and when the space freed up she stayed in the middle seat. I was only irritated because the PSP’s viewing angle is crap and I couldn’t figure out what it was she was laughing at.