Rock-bottom (some people call it a 'breakdown' or 'a really bad time') is not a nice place. Horrible, in fact.
But like when a computer freezes, turning off and on is sometimes the only thing that will work. It's the reset needed to unfreeze.
Running at full capacity all of the time is unstable and unrealistic.
That's why it's OK to see rock-bottom (or a breakdown or really bad time) as an opportunity, and not as something all bad. It gives us the necessary reset to reassess, recharge and unfreeze.