A thought in here I think I see that I like is the idea of relative comparability. That your best feeling can only be as good as your worst was bad.

IE:

In a sine wave you have to apex, a + and a - and within each frequency, the apex will be equivalent on their respective side. You can increase or decrease amplitude, but the apex on either side will increase or decrease to match. Metaphorically, life is like this...up>down>up>down kind of like waves. But, at least in my experience, the worse your downs get, the better your ups can get.

I think Nietzsche was saying you should force the downs to happen and force them to be worse so that you can intensify your ups. Which is stupid, IMO, because even if this is how it works the best and worst feelings would be relative and if everyone started with the same scale of ability to pleasure or pain, no one would be aware that you could feel better or worst than their best or worst until they felt better or worse than those apex feeling.

Bit of a tongue twister at the end there sorry.