Actually, in this case it's not really the bus, it's the people on it... I've been uncomfortable on the past few bus rides I've been subjected to, having witnessed things I didn't really want to see...
Subject A - he sat in the sideways seat a few feet ahead of me near the back of the bus... he obviously had a nervous disorder of some sort, as he constantly fidgeted and looked around like the CIA were after him... the rather yucky part was that he kept picking himself... his nose, eyes, ears, face, hair, it was like he had a million itches and was determined to scratch them all... what was worse, he would pick and then look at his fingers as if he'd caught something and begin again on another area... at one point he scratched into his face enough that it started bleeding and he proceeded to clean himself off by licking his finger and wiping it all over his face... I fixated my gaze on lampposts, but I can only turn my head so far around and the bus was nearly full except for the empty seats between he and I... blech.
Subject B - she stood at the same bus stop as I did, not making a sound... as soon as she got on the bus she started hacking and coughing until I thought she would have to eventually dislodge the alien caught in her chest... luckily I was three seats back, but the girl she was sitting next to looked traumatized... I know I didn't exactly feel all that well after 20 minutes of hearing that, I certainly didn't feel very clean... I was wondering what was in the air... ick...
Subjects C, D and E - surround and conquer, they used that tactic... fat little old lady and crabby little old man had a war of words two seats in front of me... it didn't last too long, thank goodness, but I was tired and it was enough to give me a headache... and of course, I had to sit next to sleeping beauty... some guy, about 6 foot 5 or more who had fallen asleep and was snoring really loudly... the back half of the bus was staring a hole through him, and thus, being beside him, everyone was also looking at me by proxy... it just made me uncomfortable...
so there, pesky bussessesses... I feel like purchasing a sound proof personal bio-dome so that I can ride the bus noise and germ free :)