For instance, the rain... As you all know, unlike other vehicles, motorcycles don't have roofs... Therefore, unless a motorcyclist wear a raincoat, it is unavoidable for him/her to get totally wet whenever it rains while he/she is riding... It is very dangerous to ride motorcycles in the rain because the road would be really slippery and our visions would be limited...

Besides that, I also have to worry about colliding with or encountering certain animals such as birds and snakes... Yes, snakes... There have been a few times already when I almost hit a snake while riding... A cobra almost bit my leg... I was happily riding my motorcycle to work when suddenly I saw a cobra at the side of the road... I tried to avoid it, but it got its head up and appeared to be in attacking mode... Just when I passed by it, it delivered a strike... Luckily, it missed my leg... I also have to avoid hitting flying birds... Just imagine hitting a bird at high speed... It must hurt real bad...

I hate vehicles that let out too much smoke... By the time I reached work, I would wished I could spray some Febreeze all over my clothes to get rid of the smell... 

If I'm not careful, strong wind can throw me off balance while riding... 

Bad road condition can also be a challenge... If the road has sand or gravels on it, I would have to be careful because those two lower the level of friction between the tires... That's why motorcyclists sometimes fell from their motorcycle while taking a turn at sandy roads... 

Besides all that, I also have to watch out for stupid drivers... I don't understand why is it so hard for some people to give signals when they want to go to the side or turn...