1) Wet leaves
2) Wet Painted lines
3) Gravel
4) Ice
5) Snow
6) Frostbite
7) Fogging, if you are wearing eyewear, like you should
8) Cars and their drivers.
9) Weather: layers7) Yetis
10) Drivers who do not clear windows
11) Sewer, manhole, water main covers (wet metal)
12) Debris hidden under leaves
13) Thinking too much lists to focus on riding
14) Drivers with poor night vision
15) Windburn