Hard

A road with an incline at around 5% can be cruised up (relatively speaking), or on the mountain bike, you can pace yourself fairly comfortably through a series of switch backs heading up.

In both these cases, you can choose to make them hard, simply by going as fast as you can, testing yourself.

You can make the choice, easy or hard.

I remember when Em and I were cycle touring through Europe, we left the ski resort of St Moritz in Switzerland and with a few km, began the climb over the first pass. It went forever and at one point I was in my lowest gear, literally working as hard as I could, simply to continue something that resembled forward motion.

There was no choice, it was hard, whether I liked it or not.

The thing about the two ideas is that, if you choose the hard when you can, you end up prepared for the hard when you don't have the choice.