There was recently an interesting debate between friends on Facebook concerning the worst Tri-Met bus.
#9 seems to have been deemed champion.
My favorite comment:
"I have to take the #9 at 9am AND at 6pm or 10pm, 5 days a week- worst bus ever! Always crowded, always filthy. One seat this morning had a pile of vomit in it with a piece of paper on top of it that read "DO NOT SIT HERE". And yet I watched 3 different people sit there. Even worse than the #72- which I affectionately call the "clothing optional" bus. Used to ride the #15 all the time when I lived by you Joel- it's got NOTHING on the #9, trust me."