update: further things that can go wrong on a bus

--You can forget something.  (i.e., a sweater)
--You can get mysteriously dirty.  ("What's that on my arm?!")
--Other passengers can misinform you about where the bus is going.
--You can overhear other passengers misinform (or, worse, potentially misinform -- you're pretty sure it's wrong, but not sure enough to correct them) other passengers.
--It can take ages to find where the bus stop you need is ... in the rain.
--People can form two lines to get a on a bus and you can't work out why and figure out eventually you're in the wrong one, but then have to go to the very end and start again.
--The driver can slam the door shut in your face.