Staying with that full glass analogy for the moment, I would think that the glass "spilling" some because it is overfilled would have to be interpreted carefully.
If the glass is spilling because more is being poured into it, and the liquid simply overflows because new liquid is being added, I would see that as "variation" and not a bad thing (just not something that increases the total experience of pleasure.
On the other hand if the glass spills because it is jostled, and the liquid spills over the edge and thus the total liquid declines, that would be a bad thing from just about every perspective, I would think.
We may be taking the "full glass" metaphor further than is useful ![]()