Just curious as to what others encounter (or avoid).

Although I commute to get into work, I take a longer route for fitness sake. The latest route (on the way home) takes me up a Cat 5 hill (according to MapMyRide), 1.1km @ 4.9% with one .28km section at 8.4%. It's tough but I have done it each time (albeit at only 12-13kph). Now that I know what a Cat 5 is like, I can only imagine what a Cat 1 or Hors Cat would be like?

What do others encounter?