I'm sure I am in the minority, but avoid bus trips wherever possible because I get horribly motion sick on them. I few years ago I had a job with a 20 minute bus commute and it was torture. I'd break out in a cold sweat every time and stagger off the bus feeling light headed and dizzy.

This does seem to be an inherent problem for me with road vehicles. I experience a similar problem riding in the back of a car. I'm not immune from motion sickness on trains, but it is an order of magnitude better.