01
The idea
People who have passed every threshold they would once have named still report feeling behind. This is not a failure of gratitude. It is a structural consequence of pursuing a direction rather than a destination: "more" has no arrival point built into it.
Seneca's observation is that poverty is a relationship rather than a quantity — the person who craves more is poor at any level of holding. The corollary is that sufficiency is also a relationship, and it is one you can set.
Which makes "enough" a decision made in advance, in specific terms, while you are calm. Not a feeling you wait for. The feeling, when it comes, comes from having named the threshold and then noticing you passed it.
02
Why this matters
An undefined target consumes everything. It has no natural stopping point, so it will take the evenings, the health, the relationships, and the other arenas, and it will always be able to justify taking more.
It also makes achievement invisible. Passing an unnamed threshold produces nothing — no marker, no relief, no adjustment — which is why the experience of success is so often reported as anticlimactic.
And it distorts risk. Someone with no defined sufficiency point keeps playing at stakes they no longer need to play at, which is how people lose things they had already won.