18) Deep rutted ice that is harder than diamonds and never melts
19) Deep very wet snow
20) chain rust
21) drivetrain upkeep
22) salt, salt, and more salt. (see #20 and #21 )
23) short days = riding frequently in darkness
24) crashing, not being able to move, then dying of exposure (maybe that's 2)
25) responding to the inevitable, "You didn't ride today did you?" queries posed by non riders.
26) having to roll with studded tires on dry pavement
27) deep cookie dough snow on top of ice in intersections